Preheat oven to 425°F. Grease a 9x13-inch baking dish with butter.
On a floured surface, roll out your pie crust and cut it into four 7x7-inch squares. If the dough is soft, place it in the fridge for 20 minutes to firm up.
15 ounces refrigerated pie crust
In a medium bowl, whisk the brown sugar and cinnamon together for the filling.
½ cup brown sugar, 1 teaspoon ground cinnamon
Place an apple in the center of a crust square. Fill with 1 tablespoon of the cinnamon sugar mixture and one piece of butter. Bring each corner of the crust up to meet at the center of the apple. Press gently to seal. Then gently pinch the edges of the dough together.
4 medium apples, 2 tablespoons unsalted butter
Repeat with the remaining apples and set aside in the refrigerator while you make the sauce.
Add the sauce ingredients to a medium saucepan over medium heat. Cook, stirring often until the butter and sugar melt and the mixture boils. Once it boils, remove it from the heat. Pour the sauce in the bottom of your baking dish.
1 cup apple cider, ¾ cup brown sugar, ¼ cup unsalted butter
Arrange the apples over the sauce. Bake for 40-45 minutes, basting the apples a few times with the sauce as they cook.
Remove from the oven, let cool for 10-15 minutes. Serve with the sauce from the bottom of the pan.