Tomato, Mushroom, and Onion Tart with Whipped Herb Goat Cheese, Romesco, and Basil Pesto
An almond-flour tart layered with caramelized onions, wild mushrooms, and ripe summer tomatoes, finished with whipped herb goat cheese, romesco, and basil pesto on the plate. A celebration of peak-summer ingredients. Naturally grain-free, gluten-free, and refined-sugar-free
Yield: One 10-inch tart (6-8 as a main, 10-12 as a starter)
Active: 45 min · Total: 1 hr 35 min (+ 30 min crust chill)
Seasona: Peak summer for tomatoes
INGREDIENTS
Almond-Flour Tart Crust
2½ cups fine-ground blanched almond flour
1 tbsp fresh thyme leaves (or 1 tsp dried)
¾ tsp sea salt
¼ cup raw grass-fed butter or ghee, cold and cubed
1 pastured egg
1 tbsp ice water (if needed)
Vegetable Filling
2 large yellow onions, thinly sliced pole to pole
3 tbsp raw grass-fed butter or ghee
½ tsp sea salt (for the onions)
1 tbsp fresh thyme leaves
8 oz mixed wild or cultivated mushrooms — cremini, maitake, chanterelles, or a blend
2 cloves garlic, minced
2 cups cherry tomatoes — or 2 medium heirloom tomatoes, thickly sliced
2 tbsp extra virgin olive oil, for the tomatoes
Sea salt and freshly ground black pepper, throughout
Whipped Herb Goat Cheese
6 oz fresh chèvre, at room temperature
3 tbsp grass-fed cream
2 tbsp fresh chives, finely chopped
1 tbsp fresh dill or tarragon, finely chopped
Zest of ½ lemon
1 tsp fresh lemon juice
Pinch sea salt and white pepper
Romesco
3 medium red bell peppers (or 1 cup good-quality jarred roasted red peppers)
½ cup raw almonds, blanched if possible (or hazelnuts)
1 small tomato (or 2 tbsp tomato paste)
3 cloves garlic, peeled but whole
1½ tsp Pimentón de la Vera (smoked paprika)
1 tbsp aged sherry vinegar
½ cup cold-pressed extra virgin olive oil
½ tsp sea salt
Pinch cayenne (optional)
Basil Pesto
2 packed cups fresh basil leaves
¼ cup pine nuts — Italian-sourced preferred
2 small cloves garlic
⅓ cup finely grated Parmigiano-Reggiano (or half parmesan, half pecorino)
⅓ cup cold-pressed extra virgin olive oil
1 tsp fresh lemon juice
¼ tsp sea salt
To Plate & Garnish
Fresh basil leaves, torn
Cold-pressed extra virgin olive oil, for finishing
Flaky sea salt
Freshly cracked black pepper
METHOD
Begin the caramelized onions first. In a heavy-bottomed skillet or Dutch oven, melt 2 tbsp butter over medium-low heat. Add the sliced onions and ½ tsp salt. Stir to coat, lower heat to low, and cook, stirring every 5–10 minutes, for 40–45 minutes — until deeply browned, jammy, and sweet. Do not rush. If they dry out, add a splash of water. Stir in half the thyme and a grind of pepper. Set aside in a small bowl with any pan juices — the onion-infused butter is worth saving for drizzling
Make the tart dough. Pulse the almond flour, thyme, and salt in a food processor. Add the cold cubed butter and pulse to coarse crumbs. Add the egg and pulse until the dough holds together when pinched — add 1 tbsp cold, filtered water only if needed. Shape into a disk, wrap in parchment, and chill at least 30 minutes.
Roast the bell peppers for the romesco. Preheat the oven to 425°F. Place whole peppers on a rimmed baking sheet and roast 20–25 minutes, turning once, until skins are blackened and blistered. Transfer to a bowl, cover, and steam 10 minutes. Peel, stem, and seed. (Skip this step if using jarred peppers.)
Make the romesco. In a food processor, combine the roasted peppers, almonds, tomato (or tomato paste), garlic, pimentón (smoked paprika), sherry vinegar, and salt. Pulse to a coarse blend — you want texture, not purée. With the motor running, stream in the olive oil. Taste and adjust. Rest at room temperature at least 15 minutes; it improves over hours.
Make the basil pesto. In a clean food processor, pulse the basil, garlic, pine nuts, and salt until finely chopped. Add the Parmigiano (if using) and pulse once or twice. With the motor running, stream in the olive oil and lemon juice. Stop as soon as it emulsifies — do not over-process. Press a piece of parchment onto the surface to prevent oxidation.
Whip the herb goat cheese. Beat the softened chèvre with a whisk until smooth. Add the cream a tbsp at a time, whisking, until light and spoonable. Fold in the chives, dill, lemon zest, lemon juice, salt, and white pepper. Refrigerate until serving.
Bake the tart shell. Lower the oven to 350°F. Press the chilled dough into a 10-inch tart pan with a removable bottom, working it evenly up the sides. Prick the base with a fork. Line with parchment and fill with pie weights or dried beans. Bake 15 minutes, remove the weights, and bake another 8–10 minutes until lightly golden. Cool.
Sauté the mushrooms. Heat the remaining tbsp of butter in a wide skillet over medium-high heat until it browns. Add mushrooms in a single layer — don't crowd them; work in two batches if needed. Leave undisturbed 2–3 minutes for a deep crust, then stir and cook another 2–3 minutes. Add the garlic and remaining thyme in the last minute. Season with salt and pepper.
Prepare the tomatoes. Halve cherry tomatoes; arrange heirloom slices on a sheet pan, drizzle with olive oil and salt, and roast at 375°F for 10 minutes — just enough to concentrate flavor without collapse. (Cherries can be added raw for a fresher contrast). For heirloom tomatoes: skip the pre-roast and add raw to the assembled tart, OR reduce the pre-roast to 6-7 minutes.
Assemble. Spread the caramelized onions evenly over the cooled tart shell. Scatter the mushrooms. Arrange the cut tomatoes on top — cut-side up if cherry (raw or briefly roasted, your choice), in a single layer if heirloom (roasted). Drizzle with olive oil. Return to the 375°F oven for 12–15 minutes, until warmed through and the tomatoes have slumped slightly.
Plate. Rest 5 minutes, then unmold onto a serving board. Slice into wedges. On each plate (or clustered around the tart), place a generous dollop of whipped herb goat cheese, a wide spoonful of romesco, and a pool of basil pesto. Scatter torn basil and flaky salt. Drizzle more olive oil. Serve slightly warm or at room temperature — this tart does not want to be piping hot.
NOURISHMENT NOTES
Summer in the body is the season of fullest expression. The circadian clock is tuned to long daylight — cortisol peaks earlier in the morning and melatonin rises later at night. Summer is also, biologically, the season of plant compounds at their most concentrated: peak-season tomatoes carry far more lycopene than their winter-hothouse counterparts; basil grown under long daylight accumulates terpenes in quantities the supermarket version never reaches; mushrooms grown outdoors harness more vitamin D from sun exposure.
Caramelized onions concentrate quercetin (an anti-inflammatory flavonoid), prebiotic inulin that feeds beneficial gut bacteria, and sulfur compounds that support phase-two liver detoxification. Long, slow heat converts harsh raw sulfur into mellow sweetness without adding sugar.
Wild or small-farm mushrooms bring beta-glucans (immunomodulatory) and ergothioneine (a mitochondrial antioxidant), and they synthesize vitamin D when exposed to sunlight the same way human skin does. Peak-season tomatoes carry lycopene whose bioavailability actually increases with gentle cooking — pairing it with fat (olive oil, butter, cheese) further improves absorption. Almond flour replaces wheat with vitamin E, magnesium, and monounsaturated fats, and its low glycemic load keeps the blood sugar response gentle alongside the natural sweetness of caramelized onions and roasted tomatoes.
Raw goat deserves particular attention. Most modern dairy sensitivities relate to A1 beta-casein dominant in commercial cow breeds; goat (and sheep milks) carry an A2-leaning casein profile and a more diverse fatty acid spectrum from animals that browse herbs and shrubs as well as grass.
Romesco's almonds provide a protein-rich, nutty-creamy base that makes the sauce satisfying without dairy. Smoked paprika contributes capsaicin, which supports circulation and digestion. Basil's terpene profile — linalool, eugenol, estragole — has documented antimicrobial and anti-inflammatory effects, and its chlorophyll content is high. Pine nuts carry pinolenic acid, studied for satiety. Cold-pressed extra virgin olive oil binds the dish together — literally, on the plate, and metaphorically across all three sauces. The polyphenols in good olive oil are heat-sensitive, which is why this recipe uses the oil primarily raw or minimally heated. That peppery sensation at the back of the throat is oleocanthal, the polyphenol studied for ibuprofen-like anti-inflammatory activity.
Variations
With sheep's milk cheese: Substitute the chèvre with fresh sheep's milk ricotta or whipped raw sheep's milk cheese (Vermont Shepherd, Old Chatham). Slightly sweeter, with a different fatty acid profile.
Autumn version (peak mushroom season): Increase the mushrooms to 12-16 oz and reduce the tomatoes to 1 cup of late-summer cherry tomatoes only. Lean into the mushroom-as-centerpiece direction. Add a small handful of fresh sage to the mushroom sauté.
With caramelized leeks instead of onions: Substitute the onions with 4 large leeks (white and pale green parts only), sliced into half-moons. Caramelize the same way. Slightly milder, more delicate.
With added protein: Add 4 oz crispy bacon, pancetta, or cured chorizo crumbled across the assembled tart before final baking. Adds salty, fatty depth.
Make ahead: All three sauces can be made up to 3 days ahead. The tart crust can be blind-baked the morning of serving. The caramelized onions and mushrooms can be made up to 2 days ahead. The fully assembled tart can be made the morning of and reheated at 325°F for 12-15 minutes just before serving
SOURCING
The whole philosophy of this kitchen is farm-to-table — organic, seasonal, local, and as close to the source as you can get. This tart, more than most, rewards real sourcing.
Heirloom or cherry tomatoes — The single most important choice. In July and August, go to the farmers' market and buy whatever is ripe that day. Heirloom varieties — Brandywine, Cherokee Purple, Green Zebra, Sun Gold — carry far more flavor and nutrition than conventional hothouse tomatoes. Do not refrigerate tomatoes; it kills their flavor irreversibly. If good tomatoes aren't available, skip this recipe until they are.
Mushrooms — Farmers' market or high-quality grocer, ideally a local forager whose name you know. Wild-foraged when in season — chanterelles in late summer, maitake in early autumn — both worth the splurge. For farmed, look for small specialty cultivators: Far West Fungi, Smallhold, your regional producer. Pre-packaged supermarket cremini are fine as a base; blend them with something more interesting if you can.
Almond flour — Fine-ground, blanched (skin removed). Bob's Red Mill Super-Fine, Anthony's, or Nuts.com Fine-Ground. Coarser almond meal with skins on produces a heavier, darker crust. Store in the refrigerator or freezer once opened — almond flour oxidizes faster than you think.
Raw butter, raw cream, fresh chèvre— realmilk.com is the directory for raw dairy. For pasteurized alternatives — Vital Farms Pasture-Raised, Kerrygold Reserve (cultured), Organic Valley Grassmilk. For chèvre: Vermont Creamery, Cypress Grove, Laura Chenel, Humboldt Fog, or any local farmers'-market goat dairy you can speak to directly. Avoid shelf-stable supermarket goat cheese logs — the flavor has been processed out.
Pastured eggs — Genuinely pasture-raised, not "cage-free" (a label that means almost nothing). Vital Farms is widely available; local farm eggs are better still. Dark orange yolks, never pale yellow.
Pimentón de la Vera — Smoked Spanish paprika, specifically from the La Vera region of Extremadura where peppers are oak-smoked for two weeks. Sweet (dulce) is standard for romesco. La Chinata or Mina, or any brand labeled Pimentón de la Vera DO. Do not substitute generic smoked paprika — it is an entirely different product.
Aged sherry vinegar — Vinagre de Jerez Reserva (2 years) or Gran Reserva (10 years). A small bottle lasts forever and transforms dressings.
Pine nuts — Italian or Mediterranean-sourced — the label will say so. Avoid Chinese pine nuts; they can cause "pine mouth," where everything tastes metallic for days. Expensive, yes. Worth it.
Parmigiano-Reggiano — If using, must be real — look for the stamped rind bearing the Parmigiano-Reggiano name, aged 24 months minimum. Grate fresh; pre-grated is lifeless.
Cold-pressed extra virgin olive oil — For the sauces especially, use your best bottle. Harvest date on the label is the signal. Use any single-estate first-press oil you trust. The oil should taste green, grassy, peppery.
Storage & Make-Ahead: Romesco keeps 5-7 days and is better on day three; pesto keeps 3-4 days in a glass jar, or 3 months frozen in small jars; whipped goat cheese keeps 2-3 days; the tart shell can be blind-baked the morning of. The assembled tart keeps 2 days refrigerated, though the tomatoes' fresh character diminishes after the first day. Reheat at 325°F for 12-15 minutes. Sauces and components keep longer if stored separately.
Even scale: for 12 guests — make two tarts, or one 12×16-inch rectangular tart (doubled). For 20+ — three tarts, triple the sauces, plan on leftovers.