Unroll each piece of refrigerated pie dough on a floured surface and cut each into 6 equal pieces.
Spoon 1 tablespoon of peanut butter into the center of each piece of dough, and place 2 slices of apple on the peanut butter. Top each square with a slice of Cheddar cheese. Dip your finger in water, and moisten the edges of each piece of dough. Fold the dough over into a triangle shape, and seal the edges.
Bake in the preheated oven until the cheese has melted and the pies are golden brown, 15 to 20 minutes.