In a Thatsa medium bowl, mix together ground beef, ketchup, onion, salt, pepper, and cheddar cheese. Divide into four equal portions and form into flat patties.
Grill and serve
In the base of the MicroPro Grill, place four patties. Place cover on patties in the grilling position. Microwave on high power 3 minutes.
Remove from microwave, flip patties. Microwave on high an additional 3 minutes.
Remove patties from grill. Wrap in butter lettuce leaves.
