Heat a charcoal or gas grill or a broiler to medium heat and put the rack 4 inches from the heat source.
If you're broiling, put the chicken in the pan in which you'll cook it.
Combine 2 tablespoons olive oil, 2 tablespoons fresh lemon juice, 1 tablespoon grated lemon zest, and 2 tablespoons freshly grated parmesan in a bowl.
Spoon some of the mixture over both sides of the chicken.
Grill or broil the chicken 4 to 6 minutes per side, or until browned and just cooked through.
Garnish with more parmesan.