Combine the beef, garlic powder, salt and pepper in a bowl. Press the beef into the bottom of a 9 x 13-inch baking dish into a flat and even layer. Bake for 20 minutes. Drain the liquid and set aside.
In a large pan heat the oil, and cook the diced onion until translucent and fragrant. Drain excess oil fully and set aside.
Slice the rolls in half lengthwise. Place the bottom of the same baking dish. Top the rolls with the cooked beef, then the onions, then slices of cheese in a single layer. Top with the top half of the rolls.
In a small bowl combine all glaze ingredients except the sesame seeds, brush the tops of the rolls liberally and sprinkle sesame seeds on top. Bake for 20 minutes, or until the bread is toasted and the cheese is melted. Slice into individual sliders and serve hot. Enjoy!