Flatten hot dog buns with a rolling pin. In a small bowl, stir together butter, garlic powder, and onion powder. Spread all over bottom side of buns.

In a large skillet over medium heat, sear hot dogs (working in batches if necessary) until charred, 2 minutes per side. Set aside.

Place bun buttered side down in skillet and top with 1/2 cup cheddar. Top with a hot dog and sprinkle with a little more cheddar and green onions.

Cover with a lid and let cheese melt, then use a spatula to close the bun.

Repeat with remaining buns and dogs.