Preparation: Preheat the oven to 190 °C.
Line a 30 cm diameter tart pan with baking paper and place one sheet of puff pastry in it. Press the dough down well and poke it several times with a fork.
Filling: Spread an even layer of jam over the dough. Reserve 1-2 tablespoons of jam for finishing.
Making diamonds: Cut strips of up to 1 cm wide from the second sheet of puff pastry using a serrated knife or a pastry cutter.
Lay the strips in a cross pattern over the jam and alternate the direction after each strip to create a diamond pattern.
Finishing the edges: Cut wider strips of about 2 cm from the puff pastry and attach them along the edges of the tart for a neat finish.
Brushing: Beat the egg yolk with the milk and carefully brush the puff pastry with a kitchen brush for a nice shine.
Baking: Place the tart in the oven and bake for 25 minutes, or until the puff pastry is golden brown and crispy.
Finishing: Heat the remaining jam with a small splash of water in a saucepan. Bring to a brief boil and mix until smooth.
Brush the diamonds with the warm jam for a glossy finish.
For an extra touch, you can mix a splash of brown rum into the jam.
Tips
Use homemade jam for an authentic taste. Experiment with different flavors jam or combine two types for a unique twist. For a festive look you can finish the cake with a pinch of powdered sugar after baking.
