Yet another reason to keep puff pastry around: so that you can throw together Sardine flatbreads in under 30 minutes. Serve them with aperitifs or cocktails:
Preheat the oven to 200°C. Thaw one eight-ounce sheet of puff pastry. Heat a tablespoon of olive oil in a small saucepan. Add half a finely diced onion and a crushed garlic clove and cook over low heat for five minutes, stirring until softened. Stir in three tablespoons of tomato purée, cook for a few minutes more, then remove from heat.
Stir in one tablespoon of capers, three anchovies, and two chopped sardines. Roll out the thawed puff pastry and cut it into 16 little squares. Brush egg wash on each square. Place a tablespoon of the sardine mixture in the middle of each square and bake for 15 minutes.
Garnish with quartered black olives. Makes 16 squares.