Ingredients:

8 tbsp. unsalted butter
2 cloves garlic, minced
2 tbsp. lemon juice
1 tbsp. parsley, chopped
To taste salt and pepper
1 tbsp. unsalted butter
2 Tbsp. extra virgin olive oil
1 1/2 lbs. Vidalia onions, sliced 1/8 inch thick
To taste salt and pepper
4 tbsp. beef stock
2 lbs. wagyu beef, ground chuck
4 ozs. shitake mushrooms, chopped and sautéed
4 ozs. cremini mushrooms, chopped and sautéed
5 whole brioche buns
As needed lettuce
As needed tomato slices
As needed gruyere, swiss and parmesan cheeses

Procedure: 

• Combine butter, garlic, salt, pepper, lemon juice and parsley in a food processor and process until smooth. Reserve.
• Heat a 12” sauté pan over medium-low heat. Melt olive oil and butter in pan. Add onions, kosher salt and fresh cracked pepper. Sauté until caramelized. Deglaze with the beef stock. Cool.
• FOR BURGER PATTIES: In a large bowl, combine ground chuck, cooled mushrooms, salt, pepper, and a quarter of the cooled caramelized onions. Mix well, handling the meat as little as possible. Divide the mixture into five 8-oz. portions, shaping into patties. Pre-heat a griddle or skillet over medium-high heat. Cook the burgers on a griddle or skillet, turning once, until done to preference. Finish with a dollop of the garlic butter.
• To assemble: Place a beef patty on each bottom roll. Top with 1/3 of the remaining caramelized onions. Place the top half of the bun next to the burger, cut-side up with the lettuce and tomato. Place equal parts of swiss, gruyere and shredded parmesan in a personal raclette cheese-melter.  Pour the cheese over the burger and onions tableside for presentation.

Recipe courtesy of Ron Letwinski, Chef de Cuisine, Orchard Lake CC, West Bloomfield Township, Mich.