French Tomato Tart with Lemon-Thyme Mustard & Heritage Olive Oil

At the Lello table

Tomatoes and mustard have the old French good sense of two ingredients that do not need improvement so much as proportion. A thin layer of lemon-thyme mustard beneath the tomatoes keeps the tart savory, bright and precise, while a last drizzle of Heritage olive oil restores freshness after baking.

Method

1. Heat the oven to 425°F / 220°C and place a sheet pan inside to heat. Line another tray or a board with parchment.
2. Arrange the tomato slices on towels. Sprinkle lightly with some of the salt and leave for 15 minutes, then blot the tops well.
3. Roll the puff pastry lightly into a rectangle or oval approximately 10 × 14 inches / 25 × 35 cm. Transfer to parchment and score a 1-inch / 2.5-cm border without cutting through. Prick the interior with a fork.
4. Spread the mustard inside the border. Scatter the breadcrumbs, then the Parmesan, over the mustard.
5. Arrange the tomato slices in slightly overlapping rows. Season with the remaining salt, the pepper and most of the thyme. Brush the border with egg wash and drizzle 2 tablespoons / 30 mL of the olive oil over the tomatoes.
6. Slide the tart and parchment onto the preheated sheet pan. Bake for 35 to 40 minutes, until the pastry is deeply golden and crisp and the tomatoes are concentrated at the edges.
7. Leave for 5 to 10 minutes before serving. Drizzle with the remaining 1 tablespoon / 15 mL olive oil and finish with the last thyme leaves.

Cook’s notes

• Breadcrumbs beneath the tomatoes are not filler; they create a small absorbent layer that protects the pastry from collapse.
• The tart is best warm or at room temperature. Refrigerator-cold tomato tart loses both aroma and texture.
• Use enough salt to wake the tomatoes up, but do not chase a pizza effect. The tart should remain refined rather than aggressively seasoned.

Substitutions

• Gruyère may replace Parmesan for a slightly softer, more melting interior layer.
• If heirloom tomatoes are unavailable, use firm plum tomatoes sliced slightly thinner and drained carefully.
• A very good Dijon can replace the L’Épicurien mustard, though the lemon-thyme version gives the tart its particular brightness.

To serve

Serve with a lightly dressed green salad, or cut into narrow rectangles for drinks. It also sits beautifully beside roast chicken at room temperature.

Storage & make-ahead

Keep leftovers refrigerated for up to 2 days. Reheat on a sheet pan at 375°F / 190°C for 8 to 10 minutes so the pastry re-crisps.