Prepare white or yellow sweet onion by slicing in thick slices, place in plastic bag or glass jar with ice water, seal and refrigerate until ready to use.
This makes the onions very crisp and juicy.
Slice a vine-ripened tomato into thick slices.
Mix sour cream, chopped green onions, bread crumbs, Worcestershire sauce and lemon pepper seasoning.
Mix this in with the ground meat until combined well.
Shape into 4 patties
.Mix the mayonnaise, mustard and catsup. Blend well.
To serve, divide the catsup mixture evenly on the warmed hamburger buns, top with a meat patty, tomato slice, onion slice and shredded lettuce.