1. Preheat oven to 375°.
2. Combine apple, toffee chips, sugar, lemon juice, and cinnamon in a medium bowl.
3. Roll the pie dough on a lightly floured surface into 2 (12-inch) circles. Using a 3-inch round cookie cutter, cut each dough portion into 12 rounds. Discard any remaining dough scraps. Place 12 dough rounds on a baking sheet coated with cooking spray. Brush half of the beaten egg over dough rounds. Spoon about 1 tablespoon apple-toffee mixture onto each round, leaving a 1/2-inch border around the edges of the dough. Top each round with 1 piece of butter. Top pies with remaining 12 rounds of dough; press edges together with a fork to seal. Brush remaining half of beaten egg over each pie. Bake at 375° for 25 minutes or until golden brown.