Why put the cheese on top of the burger when half of it just melts off? Instead, form the burger around the cheese so you can char the meat and safeguard the more delicate flavors. Use any mixture of hard or semihard cheeses--Emmentaler and Gouda or Asiago and Parmigiano-Reggiano also pair well.
- Preheat grill to medium-high or preheat the broiler.
- Combine Cheddar and Gruyere in a small bowl.
- Gently mix beef, Worcestershire, paprika and pepper in a large bowl, preferably with your hands, without overworking. Shape into 8 thin, 4-inch-wide patties. Mound 2 tablespoons of the cheese mixture on each of 4 patties, leaving a 1/2-inch border. Cover each with one of the remaining patties. Crimp and seal the edges closed.
- To grill: Lightly oil the grill rack (see Tip). Grill the stuffed patties over medium-high heat, about 4 minutes per side for medium-well. (Be sure not to press the burgers as they cook or they’ll split open and the cheese will ooze out.) To broil: Cover a broiler pan with foil and coat with cooking spray. Broil the stuffed patties in the upper third of the oven, about 4 minutes per side for medium-well. In either case, let the burgers stand for 5 minutes before serving.