For the puff pastry jam corners, cut the puff pastry into 8 squares. Preheat the oven to 200 °C. Beat the egg in a small bowl and whisk with a fork.
Brush the edges of the puff pastry squares with the beaten egg. Place a teaspoon of jam in the center of each puff pastry square.
Then fold the pastry pieces together to form triangles. Press the edges well so that the jam does not drip out during baking.
Place the filled puff pastry pieces on a baking tray covered with baking paper and brush with egg. Bake at 200 °C until the dough has risen nicely and has acquired some color.