In a large bowl whisk together the flour, instant yeast, sugar, and salt. Make a well and add warm water (about 38°C) and 2 tbsp olive oil. Stir with a wooden spoon until a shaggy dough forms.

Knead

Turn the dough onto a lightly floured surface and knead 6–8 minutes until smooth and slightly elastic. If using a stand mixer, knead with the dough hook on medium-low for 5 minutes.

First rise

Form dough into a ball, coat lightly with oil, place in a bowl, cover with plastic wrap or a clean towel, and let rise in a warm draft-free spot until doubled, about 60–75 minutes.

Shape

Gently deflate the dough and roll or press into a 12x10-inch (30x25 cm) oval or rectangle on a parchment-lined baking sheet, leaving the edges slightly thicker to form a rim. Cover and let rest while preparing toppings, about 20 minutes.

Confit d'oignons (Onion topping)

Prepare onions

While the dough rises, heat 2 tbsp olive oil and 1 tbsp butter in a wide skillet over medium-low heat. Add the thinly sliced onions and 1 tsp sea salt; toss to coat.

Slow-cook

Reduce heat to low and cook the onions gently, stirring occasionally, 30–40 minutes until very soft and translucent but not browned. If they begin to brown too quickly, lower the heat and add a splash of water.

Finish confit

When onions are soft, add 1 tsp sugar, 2 tbsp dry white wine (or vermouth), and 1/2 tsp freshly ground black pepper. Cook 3–5 minutes more until wine has mostly evaporated and mixture is glossy. Taste and adjust salt.

Cool slightly

Remove from heat and let the confit cool slightly so it’s easy to spread on the dough (about 10 minutes).

Assembly & Bake

Preheat oven

Preheat the oven to 220°C (425°F). If you have a baking stone, place it in the oven while preheating and use a baking sheet on top of it; otherwise use the parchment-lined baking sheet with the dough.

Spread onions

Spread the cooled onion confit evenly over the dough, leaving a 1/2-inch (1 cm) border. Press the onions slightly to form a compact layer.

Arrange anchovies & olives

Lay anchovy fillets across the onion layer in diagonal rows or a crisscross pattern (about 12 fillets), spacing evenly. Tuck pitted olives between anchovies to create a decorative pattern. Scatter capers if using and sprinkle fresh thyme leaves.

Bake

Brush the exposed rim with 1 tbsp olive oil. Bake in the preheated oven on the middle rack for 15–20 minutes, until the crust is golden and crisp and the topping is bubbling slightly.

Finish & season

Remove from oven and transfer to a cooling rack. Immediately sprinkle coarse sea salt (about 1/4 tsp) and 1/4 tsp freshly ground black pepper over the tart. Drizzle a little extra virgin olive oil over the top.

Rest & serve

Let the pissaladière rest 5–10 minutes, then slice into 8 pieces. Serve warm or at room temperature.