Start by thawing out the puff pastry. Set aside
Clean and peel your apples. Slice about 1/8th of an inch thick! In a small bowl mix together sugar and cinnamon. Toss 3/4 of the sugar with the apples. Save the remaining cinnamon sugar.
In another bowl, melt all of your butter and pour 1/4 cup butter over apples and mix well. Toss apples with cornstarch until well combined.
Roll out your puff pastry into an even thickness. Shape really doesn't matter, mine resembled a rectangle. Use a fork to make a few holes into the bottom of the dough.
Pour the apples into the center of the dough leaving about 2 inches on each side. Fold in the edges of the dough to secure the filling.
Brush remaining butter on the crust and sprinkle with leftover cinnamon sugar.
Bake at 400 for 20 minutes or until nice and puffed, lightly brown and crispy. Serve with ice cream and enjoy!