It’s All In The Burger Recipe

Heat the butter in a skillet over medium heat, and cook and stir the red onion for about 5 minutes until soft and translucent.

Mix the ground beef, cooked onion, mushrooms, ketchup, egg yolks, Worcestershire sauce, horseradish mustard, black pepper, and sea salt in a large bowl until thoroughly combined.

Form the mixture into 6 ¾-inch thick patties and cook in a large skillet over medium heat for 5 to 7 minutes per side until the burgers are juicy and browned,

An instant-read meat thermometer inserted into the center of a patty should read at least 160 degrees F.