Make brown butter: in a medium pot, melt butter over medium heat. Then turn heat down to low. Cook, whisking occasionally, until milk fats separate out and slightly brown on the bottom of the pot. It should smell slightly nutty. Cook for about 10 minutes, or until this process is complete and butter is fully browned but not burnt.
Remove from heat when the brown butter smells very nutty. Strain off most of the solids and add the liquid to a small mixing bowl. Nest the small mixing bowl in a larger bowl filled with ice water. Stir to quickly cool and set the brown butter.
Use your hands to mix the chilled brown butter mixture (in pea-sized chunks) into the ground beef. Form meat mixture into six 6-oz. burgers and season them well with salt and pepper.
Cook burgers over medium-high heat in a cast iron skillet for 4-5 minutes per side to form a nice crust. During the last few minutes, top burgers with cheese and cover to melt.
Alternatively, you can grill the burgers over medium-high direct heat for 4-5 minutes per side. Note: Because these burgers have a lot of fat, you may experience flare-ups as you grill them so be cautious and keep a squirt bottle handy with some water in it to help douse the flames.
Serve burgers on toasted Martin’s Sandwich Potato Rolls topped with lettuce, onions, and other desired condiments.
Recipe adapted from: www.macheesmo.com