Fry bacon and set aside, reserving bacon bits
Mix 1 pound ground beef with 2 tablespoons ranch seasoning, 3 tablespoons sour cream, bacon bits, and 1 cup grated sharp cheddar cheese until thoroughly combined
Separate mixture into 4 ounce patties
Heat griddle to high temperature
Place burger patties on griddle and smash them down
Grill onions separately
Spread burger buns with mayonnaise and toast on grill
Mix ketchup and mayonnaise for burger sauce
Assemble burgers with grilled onions, bacon, and sauce
Serve immediately
