Bacon and cheese (by Jim Hebson, co-owner of Chicago burger institution Hackney’s): Form 1 pound ground beef into 3 to 4 patties, and split each patty in half lengthwise. Make a dimple in 1 half of each burger and insert 1 heaping teaspoon shredded cheddar and 1 heaping teaspoon crumbled bacon. Put halves back together and seal sides. Alternative suggestion: Fry burger in bacon grease. Or go all out and attempt the Minneapolis Jucy Lucy.
Chipotle (by Scott Youkilis, chef/owner of San Francisco’s Maverick restaurant): Into 1 pound of ground beef mix 2 to 3 canned chipotle peppers in adobo sauce puréed in a food processor or minced. Form into 3 to 4 patties and cook. (Youkilis recommends topping with pepper jack cheese, avocado, grilled red onion, and shredded cabbage—no lettuce.)
Roasted red pepper (by Scott Youkilis): Roast 1 red pepper and peel. Julienne 3 medium onions and caramelize over medium-low heat with 2 tablespoons butter. Purée pepper and onion with just enough water to make a paste; mix with 1 pound ground beef. Form into 3 to 4 patties and cook.
Foie gras (by Adam Longworth, sous-chef at New York City’s Gotham Bar and Grill): Dice 1 small white or Vidalia onion, 2 cloves garlic, and 1 small shallot. Cook over medium-low heat in 1 tablespoon butter until completely tender and caramelized. Stir in 1 tablespoon minced parsley and 1 tablespoon minced chives. Mix with 1 pound ground beef. Dice 2 ounces foie gras and fold into beef. Form into 3 to 4 patties and cook.
Salami (by Josh Epple, owner of San Francisco’s Drewes Bros. Meats): Form 1 pound ground beef into 3 to 4 patties, and split each in half lengthwise. Place 1 slice of prosciutto or Italian salami between each 2 half-patties. Form into 3 to 4 patties and cook.