Filling can be made 1 day ahead and chilled, covered. Bring to room temperature before using. ? Pissaladi?re strips can be baked 3 hours ahead and kept, uncovered, at room temperature.
Ingredients
For filling
* 1 medium onion, finely chopped
* 2 flat anchovy fillets, rinsed and chopped
* 1/2 cup chopped red bell pepper
* 1/2 cup chopped yellow bell pepper
* 1/2 teaspoon finely chopped fresh rosemary
* 3 tablespoons extra-virgin olive oil
* 1/2 cup Ni?oise or other brine-cured black olives, pitted and coarsely chopped
For dough
* 1 1/3 cups all-purpose flour
* 2 teaspoons baking powder
* 1/2 teaspoon salt
* 3 1/2 tablespoons cold unsalted butter, cut into small pieces
* 1/2 cup whole milk
Directions
Make filling:
Cook onion, anchovy, bell peppers, rosemary, a rounded 1/4 teaspoon salt, and 1/8 teaspoon pepper in oil in a heavy medium skillet over medium heat, stirring occasionally, until onion is golden, about 10 minutes. Transfer to a bowl and stir in olives, then cool filling.
Make dough while filling cools:
Preheat oven to 400