Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a skillet over medium heat, add olive oil and cook the onion and bell pepper until softened.
Add ground beef and cook until browned. Drain excess fat.
Stir in tomato sauce, cumin, salt, and pepper. Simmer for 5 minutes, then remove from heat and let cool slightly.
Roll out pie crusts and cut into 4-5 inch circles using a cookie cutter or glass.
Place a spoonful of filling in the center of each circle. Fold over and press edges with a fork to seal.
Transfer empanadas to the baking sheet. Brush tops with beaten egg.
Bake for 20-25 minutes, or until golden brown. Let cool slightly before serving.