Brown beef and onion in a large skillet over medium-high heat 7-8 minutes, breaking up beef with a spoon. Drain excess fat if needed.

Stir in ketchup, brown sugar, Worcestershire, mustard, and garlic powder.

Reduce to low; simmer 10-12 minutes, stirring occasionally, until sauce thickens. Season with salt and pepper.

Toast buns if desired; fill generously. Serve immediately with chips or a side salad.