Be sure to have all your ingredients prepped as this goes fast. Turn oven to broil. Heat a cast iron pan over medium heat. Add tallow.

When hot, add burger in 4 hunks and smash down with a fork to about 1/2 in thick. (No need to shape and get messy hands) Add tomato and avocado slices directly on to pan to fry. Liberally sprinkle with salt and pepper. Flip burgers after about 3 minutes and bottoms are brown.

Top with hot tomato and avocado. Top with a slice of cheese or Maria's brown butter cheese sauce. Transfer pan to the oven and broil 3-5 minutes in the oven to melt cheese.