Step 1: Preheat Oven and Prepare Puff Pastry.

Preheat the oven to 375°F (190°C).

Unfold the thawed puff pastry sheet on a lightly floured surface or parchment paper.

Use a sharp knife to score the edges of the puff pastry, about 1 centimeter in from the edges. Don’t cut all the way through. This creates a border.

Use a fork to prick the interior of the puff pastry thoroughly. This prevents it from puffing up too much in the center.

Step 2: (Optional) Egg Wash.

If desired, brush the beaten egg along the scored edges of the puff pastry. This will give it a golden brown color and a nice sheen.

Step 3: Bake the Puff Pastry.

Place the puff pastry on a baking sheet.

Bake for 15 minutes, until puffed and golden brown.

Step 4: Press Down the Center.

Use a spatula to gently press down the interior of the puff pastry, separating it from the raised crust. This creates a well for the filling.

If you desire a more golden and baked puff pastry, bake for 3 more minutes.

Step 5: Add the Filling.

Spread the chocolate hazelnut spread evenly in the center of the puff pastry, within the scored border.

Arrange the sliced strawberries in a single layer on top of the Nutella.

Step 6: Slice and Serve.

Slice the tart into squares or rectangles.

Serve immediately. The puff pastry is best enjoyed fresh.