Preheat oven to 400° F / 205° C. Line a half-sheet rimmed baking tray with parchment or a silicone mat.

On a silicone rolling mat or lightly floured countertop, gently unroll the puff pastry. Use a rolling pin to make the pastry a few inches wider, or a knife to trim away any excess. When finished, you should have a 9 x 12-inch rectangle. Position the rectangle with the longer side facing you.

With a sharp chef’s knife, slice a 3-inch wide strip of the pastry. Set the larger piece of pastry aside.

Use a 1-inch star cutter to cut the smaller strip of pastry into 12 stars.

With a small stepped palette knife, spread the pesto on top of remaining pastry rectangle.

Slice into 3/4-inch-wide strips. You should have 12 strips total.

Working one at a time, fold each strip of pastry back-and-forth in a zigzag movement, forming a Christmas tree shape.

Push a long wooden skewer through each tree. Place on prepared tray.

With a pastry brush, brush the white sides of each tree with beaten egg.

With a pastry brush, add a dab of egg wash to the top of each tree, then place a star on top. With your fingertips, press down gently to secure.

Lightly brush the stars with egg wash.

Bake in preheated oven for 15-18 minutes, or until pastry is flaky and golden brown.

Allow puff pastry trees to cool briefly on a wire rack.

Garnish with grated Parmesan. Serve warm or at room temperature.