Step by step

Method

4 steps

1. 1

   Heat the oven to 400°F. Cook 3 large thinly sliced yellow onions with 2 tablespoons olive oil and ½ teaspoon kosher salt in a wide skillet over medium-low heat 25–30 minutes, stirring often, until soft and golden. Stir in 1 teaspoon dried thyme and ¼ teaspoon black pepper.

2. 2

   Unfold 1 sheet thawed frozen puff pastry on a parchment-lined sheet pan. Score a ½-inch border without cutting through.

3. 3

   Spread the onions inside the border. Arrange 8 oil-packed anchovy fillets (optional but classic) in a lattice or spokes on top, and scatter ⅓ cup pitted Niçoise or Kalamata olives over everything. Brush the pastry border with 1 beaten egg.

4. 4

   Bake 22–28 minutes until the pastry is puffed and deep golden. Cool 5 minutes, slice, and serve warm or at room temperature. You want a savory pissaladière-style tart with sweet onions, olives, and anchovy — not soggy pastry or bitter burned onions.