Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a large pot, bring salted water to a boil. Add the potatoes and cook for 15-20 minutes until fork-tender.

Heat a tablespoon of olive oil in a skillet. Sauté the onions for about 5 minutes until they become translucent.

Add ground beef to the skillet, breaking it apart as it cooks. Season with garlic powder, salt, and pepper, and cook for 7-10 minutes until browned.

Combine the smooth mashed potatoes, browned beef, and shredded cheese in a mixing bowl. Mix until fully integrated.

On a floured surface, roll out the potato mixture to about 1/4 inch thick and cut into 4 to 5 inch squares.

Place a generous spoonful of the beef-cheese mixture in the center of each square, fold over and press edges to seal.

Brush the tops with the egg wash and bake on the parchment-lined sheet for 20-25 minutes until golden.

Allow pockets to cool for a few minutes before serving with a side of ranch dressing or marinara sauce.