Heat a skillet over medium heat. Add ground beef and chopped onion. Cook until the meat turns brown and onions become soft. Stir often to prevent sticking. Drain extra grease if needed. This creates a flavorful and hearty filling for the hot pockets.

Sprinkle garlic powder, paprika, salt and black pepper over the cooked beef. Add ketchup and mustard into the skillet. Stir everything together until fully mixed. The seasonings create a smoky and savory flavor that tastes warm and comforting in every bite.

Turn off the heat and let the beef cool slightly. Add cheddar cheese and mozzarella cheese into the mixture. Stir gently until slightly melted. The cheese makes the filling creamy and rich. It also helps hold the filling together inside the dough.

Preheat your oven to 400°F or 200°C. Roll out the pizza dough on a lightly floured surface. Cut it into equal rectangles using a knife or pizza cutter. The dough should be thick enough to hold the filling without tearing during baking.

Place a spoonful of beef filling in the center of each dough rectangle. Leave space around the edges for sealing. Avoid overfilling because the pockets may open while baking. The filling should sit evenly for balanced flavor and easier folding.

Fold the dough over the filling to create pockets. Press the edges firmly with a fork to seal tightly. This keeps the cheesy filling inside while baking. Place the pockets carefully on a parchment-lined baking tray with enough space between them.

Brush beaten egg over the top of each pocket. This helps create a shiny golden crust after baking. Sprinkle sesame seeds or parsley on top if desired. The toppings add extra texture and a homemade bakery-style appearance to the finished pockets.

Place the tray into the preheated oven. Bake for 20 to 25 minutes until golden brown and crispy. The crust should feel firm and lightly crunchy. Let the hot pockets cool for a few minutes before serving because the filling stays very hot inside.