The secret to great hamburgers is in the ingredients, according to chef Michael Lomonaco. He recommends using equal parts sirloin and chuck.
Source: The Martha Stewart Show, February Winter 2007
1 pound ground sirloin
1 pound ground chuck
Coarse salt and freshly ground black pepper
2 tablespoons olive oil
Sliced cheddar cheese, for serving (optional)
4 brioche burger buns, split
Sliced tomatoes, for serving (optional)
Red Onion Jam (http://www.marthastewart.com/259093/red-onion-jam), for serving
In a large bowl, mix together sirloin and chuck. Gently form into 4 equal patties. Season patties with salt and pepper.
Preheat a grill pan or large skillet over medium-high heat. Oil a grill pan or skillet. Heat for 1 minute; add patties. Cook, turning once, about 4 minutes per side for medium-rare. Cook 1 or 2 minutes longer per side for a more well-done burger. Top burgers with cheese if desired, and cook until melted.
Place each burger on a bun, and serve with tomatoes and red onion jam, if desired.