Step 2: Prepare the Apples
In a large mixing bowl, combine the sliced apples with sugar, lemon juice, cinnamon, nutmeg, and cornstarch. Toss until the apples are evenly coated, then set aside.
Step 3: Assemble the Pie
Unroll the puff pastry sheet onto the prepared baking sheet. Arrange the apple slices in an overlapping pattern on one half of the pastry, leaving a 1-inch border around the edges. Dot the apples with small pieces of butter for added richness.
Fold the other half of the pastry over the apples to create a half-moon shape. Press the edges together firmly and crimp with a fork to seal. Use a sharp knife to cut a few small slits in the top to allow steam to escape.
