Preheat oven to 400°F Lightly grease 2 baking sheets.
In a large skillet, combine ground chuck, onion, and bell pepper. Cook over high heat until mixture is browned and crumbly; drain.
Return meat mixture to pan, stir in tomato sauce, tomato paste, garlic salt, sugar, and pepper.
Reduce heat to medium, and simmer 20 minutes. Remove from heat, and cool slightly. On a lightly floured surface, unroll pie crusts.
Using a 5-inch round cutter, cut 5 circles from each crust, re-rolling dough as necessary. Spoon 2 tbsp meat mixture into center of each round, sprinkle with 1 1/2 tsp cheese; lightly brush edges of pie crust with beaten egg yolk.
Fold dough over to enclose filling, crimping edges to seal. Place pies on prepared baking sheets; bake 20 minutes. Serve immediately.