Place butter and oil in a frying pan or on the grill (I start on the stove and finish cooking on the grill when I start cooking my burgers) and heat until butter has melted. Add the onion that has been cut into layers or long strands. Salt and pepper your onions. Grill or cook your onion stirring frequently until it becomes almost golden brown throughout. Add the beer and continue to heat until almost all of the liquid has been cooked off. Remove from heat and let the onion cool on the counter. Put onion on your favorite burger and finish your beer.