Perfectly seasoned, juicy ground sirloin burgers, sauteed onion, and Cheddar cheese come together for a heavenly patty melt experience!
Mix sirloin, Worcestershire sauce, garlic, salt, and pepper together by hand in a medium bowl. Form into 4 hamburger patties and wrap in plastic wrap. Place in the refrigerator until flavors have melded, 4 hours to overnight.
Heat butter and olive oil in a large skillet over medium heat until melted. Add onions and saute until they begin to caramelize, about 15 minutes, reducing heat to medium-low if they seem to be sizzling too much.
Spray a large skillet with cooking spray and heat over medium heat. Place hamburger patties in the skillet and cook for 3 minutes per side, topping each patty with a slice of Cheddar cheese after flipping.
Place patties on toasted rye bread. Top with warm onions, Dijon mustard, and remaining bread.
Per Serving: 621 calories; protein 33g; carbohydrates 39g; fat 36.9g; cholesterol 101.6mg; sodium 1100.6mg.