I could live on this… and some rosé. Famous French salty topping of sautéed onions, anchovies, and olives gets a little update with an addition of ripe cherry tomatoes. Their roasted sweetness balances perfectly such intensive saltiness of the gutsy fish and olives.
Makes three 9-inch round tarts; each about 6 to 8 servings
For the dough (start a day before baking):
- ½ cup milk, lukewarm
- 2 ¼ tsp (1 package) active dry yeast
- 3 cups all-purpose flour
- 3 tbsp granulated sugar, divided
- 2 tsp kosher salt
- 8 tbsp (1 stick; 113g) unsalted butter, melted and cooled
- 3 large eggs, at room temperature, whisked
For the topping (the topping recipe is adapted from Elisabeth Prueitt):
- About ¼ cup olive oil
- 18 oz (1 lb 2 oz) yellow onions, thinly sliced
- Freshly ground black pepper
- 1 ½ tsp white wine vinegar
- 6 tbsp water
- 4 ½ oz Niçoise olives, chopped
- 2 cans anchovies (2 oz each), each fish fillet sliced lengthwise
- 1 pint cherry tomatoes, halved
- Fresh thyme, chopped
- 1 large egg yolk
- 1 tbsp whipping cream
Make the dough:
In a liquid measuring cup, combine the warm milk, 1 tsp sugar, and the yeast. Stir to dissolve. Cover with plastic wrap and let stand in a warm place until the mixture bubbles and doubles in size, about 10-15 minutes.
Meanwhile, in the bowl of a standmixer, whisk the flour, remaining sugar, and salt. Make a well in the center and, with a wooden spoon, stir in the yeast mixture, followed by the melted butter and whisked eggs. Stir until combined. Attach the bowl to the base of the stand mixer, and knead with the dough hook for about 8 minutes on medium speed. The dough should clear the sides of the bowl but stick to the bottom. Transfer the dough into a large oil-sprayed bowl, cover the bowl with oil-sprayed plastic wrap, and place into a warm place until the dough has doubled in volume, for about an hour. Deflate the dough, then place the dough in the same bowl, covered with plastic, in the refrigerator overnight.
Make the topping, bake the tarts:
Center an oven rack and preheat the oven to 375F. Butter three 9-inch round tart pans with removable bottom. Set aside.
Heat the oil in a large heavy sauté pan over medium-high heat. When the oil is hot, add the onions, season them with salt and pepper, and sauté, stirring often, until the onions have reduced and are golden brown. Add the vinegar and water, stir well, and scrape up any brown bits from the pan bottom. Remove from the heat and let cool to room temperature.
Divide the chilled dough into three equal portions, each about 10 oz (280g). On a lightly floured surface, roll out each dough portion into a circle just large enough to fit onto the bottom of the tart pan. Transfer the dough to the prepared pan, making sure it fits all the way to the sides (but not up the sides) of the pan. Top each dough round with 1/3 of the sautéed onions, leaving a ½-inch border uncovered around the sides. Then arrange the lengthwise-sliced anchovy fillets over the onions, forming a lattice pattern. Sprinkle 1/3 of the chopped olives over each tart, then place the tomato halves, cut side up, into each diamond, formed by the anchovy fillets. Cover each tart loosely with oil-sprayed plastic wrap and place into a warm place to proof, for about 45 to 1 hour.
In a small bowl, whisk together the egg yolk and cream together. Lightly brush the uncovered edges of the tarts with the yolk mixture (the most delicate way to apply the mixture is by using your finger; the dough is very soft). Bake the tarts for about 30-35 minutes, until the crust is golden brown and onions have further caramelized. Let cool on a rack for 10 minutes, then unmold. Cool on the rack.
Serve slightly warm or at room temperature the same day the tarts are baked, sprinkled with fresh thyme.