Preheat your oven to 180 C. In a 9x13 baking dish, add the ground beef, salt, pepper, and garlic powder, mixing thoroughly and pressing it into a flat, even layer. Bake for 20 minutes.
Using a large spatula or two, remove the cooked beef and set aside, drain the fat from the dish and just use paper towels to wipe out the dish, DO NOT pour cold water in the dish if you are using a Pyrex dish!
Slice the rolls in half lengthwise, slice the entire package at one time, not individually. Place the bottom half in a 9x13 baking dish.
Place the cooked beef layer on the rolls, followed by the onions and cheddar. Place the remaining half of the rolls on top.
Brush with melted butter and sprinkle with sesame seeds to your liking. Bake for 20 minutes.
Slice into individual sliders, serve, and watch your fingers!