The recipe can be found online here but I've summarized the recipe below:
onion (sliced in rings)
crimini mushrooms, sliced
black olives, chopped
green chile (canned or charred/peeled/sliced)
Make the burgers.
Sauté the onions in olive oil and when they've softened up, then add the mushrooms. Once that has cooked for a few minutes add the green chile and olives. Cook that for a few more minutes.
You can use on pan or two to prepare the burgers and toppings, but once the onion mixture is ready you need to return the burgers to the pan and top them with the mixture. Place a slice of cheddar cheese on top and then add some beer to the pan and cover immediately. Let the burgers steam in the beer while the cheese melts and then serve on buns. It's great accompanied by a wedge of lettuce and veggies for a salad.
I can't wait to make this recipe!