Grate the onion, throw in or throw away the small onion pieces, don't grate your fingers.
Depending on the size of your buns, divide the ground into the number of patties you want. Make sure the beef portion is bigger than the buns.
Use your thumb to make a hole in the beef and add about a teaspoon of butter, roll to cover the butter, then press flat. Press the middle of the patty to create a small hole this will help with puffing of the beef while cooking.
Repeat until you finish all the ground beef mixture.
Grease your skillet or grill, let it get hot
During the final minute or so place a cheese over the patty to melt, remove the patties when they are done and cover with an aluminum (like a tent) to keep them warm. Repeat the process until you're with the patties.
For the sauce, I used an equal part of mayonnaise and ketchup then mix. Use any sauce of your choice.
To Assemble: Slice the tomatoes and grilled some sliced onions (optional)
Place a slice/ring of grilled onion
Serve with some chips/bbq chips and enjoy!