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. With a rolling pin, roll the pastry a few inches wider, or use 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 from the shorter side of the pastry. You should now have a 3 x 9-inch rectangle, and a 9 x 9-inch square. Set the larger piece of pastry aside.

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

With a small stepped palette knife, spread the pesto on top of remaining 9 x 9-inch piece of pastry.

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.