Preheat your oven to 400°F (200°C).

In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until soft and translucent, about 4-5 minutes.

Stir in the minced garlic and cook for an additional minute until fragrant.

Add the ground beef to the skillet, breaking it apart with your spatula. Cook until the meat is brown and cooked through, about 6-8 minutes. Drain any excess fat.

Remove the skillet from heat and stir in the ketchup, mustard, salt, and pepper. Mix in the shredded cheddar cheese until it melts and everything is well combined.

On a floured surface, roll out one pie crust. Cut it into four equal squares.

Place a generous spoonful of the cheeseburger mixture onto one half of each square, leaving enough space to fold.

Fold the other half over the filling, creating a pocket. Press the edges with a fork to seal.

Repeat with the second pie crust and remaining filling.

Place the hot pockets on a baking sheet lined with parchment paper. Brush the tops with the beaten egg for a golden finish.

Bake for 15-20 minutes, or until golden brown and puffed up.

Remove from the oven and let them cool slightly before serving.