Preheat your oven to 375°F and line a baking sheet with parchment paper.
In a large skillet over medium-high heat, cook the ground beef, breaking it up as it cooks, until no longer pink, about 6–8 minutes. Drain any excess grease.
Season the beef with garlic powder, onion powder, salt, and pepper. Stir to combine.
Add the ketchup, mayo, and diced pickles to the skillet. Stir everything together and cook for 1–2 minutes.
Open the can of Pillsbury biscuits and on a lightly floured surface, roll out each biscuit flatten to be about 5 inches in diameter.
Add cheese, then a generous spoonful of the beef filling followed by more cheese.
Pinch the sides together and close tightly in the middle.
Transfer the pockets to the prepared baking sheet. Beat the egg and brush it over the tops of the pockets. Sprinkle with sesame seeds if using.
Bake for 18–22 minutes, or until the pockets are deep golden brown. Let cool for a few minutes before serving.