Miniature Onion Tartlets

Ingredients

• 3 fillet to 4 flat anchovy dry finely chopped
• 0.3 teaspoon pepper black
• 2 teaspoons thyme leaves fresh chopped
• 0.3 cup kalamata black pitted very thinly sliced lengthwise
• 3 tablespoons olive oil 
• 12 oz onion halved lengthwise
• 1  puff pastry sheet frozen thawed
• 0.5 teaspoon salt 

Equipment

• frying pan
• baking sheet
• oven

Directions

1. Preheat oven to 400°F.
2. Roll out puff pastry on a lightly floured surface into a 12 1/2-inch square, then trim edges to form a 12-inch square. Prick sheet all over with a fork.
3. Cut into 36 (2-inch) squares and transfer to 2 buttered large baking sheets, arranging about 2 inches apart.
4. Bake in upper and lower thirds of oven, switching position of pans halfway through baking, until puffed and golden, 12 to 15 minutes total.
5. Transfer squares to a rack and cool until just warm.
6. While pastry is baking, heat 2 tablespoons oil in a 12-inch nonstick skillet over moderate heat until hot but not smoking, then cook onion with salt and pepper, stirring occasionally, until golden brown, 15 to 20 minutes. Stir in anchovies (to taste) and 1 teaspoon thyme and keep warm, covered.
7. Lightly brush tops of pastry squares with remaining tablespoon oil. Make a small indentation in center of each square with your finger, then top each with 1 teaspoon onion mixture and a few olive slivers.
8. Sprinkle squares with remaining teaspoon thyme.
9. ·Pastry squares can be baked 1 day ahead, cooled completely, and kept in an airtight container at room temperature. Reheat in a 350°F oven 6 minutes before topping. ·Onion mixture can be made 1 day ahead and chilled, covered. Reheat over moderate heat, stirring, until heated through, about 10 minutes.