Flaky pastry crescents filled with onion, tomato, and mozzarella are Catania's breakfast or snack of choice. This mediterranean pastry is a family-friendly vegetarian treat.
Preheat your oven to 400°F. Line a large baking sheet with parchment paper for even heat distribution.
Peel and thinly slice the onions. In a pan, heat the olive oil over medium heat, then slowly cook the onions with a pinch of salt until soft and golden, about 20 minutes, stirring occasionally to prevent browning.
Dice the tomato and season it with a little salt and the dried oregano. Drain any excess juices.
Cut mozzarella into medium cubes and gently pat dry to remove excess moisture, helping prevent soggy pastry.
Unfold the thawed puff pastry sheets and cut each into 3 large rectangles. Layer sautéed onion, seasoned tomato, and mozzarella on one half of each rectangle. Sprinkle with a pinch of black pepper.
Fold the pastry over the fillings to make crescents or rectangles, seal the edges tightly, and crimp with a fork. Place on prepared baking sheet. Beat the egg and brush the tops for a glossy finish.
Bake for 22–25 minutes, rotating the pan halfway through, until the pastries are puffed and deep golden. Transfer to a rack and let cool slightly before serving warm.