I used straight up EVOO (extra virgin olive oil) instead of butter to save some calories. I cooked sliced onions in EVOO in a cast iron skillet, fried a hamburger patty seasoned with S & P, then in a another cast iron skillet I grilled it all together in between two slices of bread allowing the cheese to melt. So much better than Jack in the Box. The plate isn’t that pretty considering this was ‘seconds’. But the Grilled Onion Patty Melt was delish!