6 tablespoons mayonnaise
2 tablespoons whole grain Dijon mustard
1 teaspoon grated lemon zest
1-1/2 pounds ground round beef
1/2 cup crumbled goat cheese
1-1/2 teaspoons kosher salt
1/2 teaspoon ground black pepper
4 brioche hamburger buns, split
8 thin slices prosciutto
4 leaves green leaf lettuce
In small bowl, stir together mayonnaise, mustard and lemon zest.
Preheat grill for direct grilling over medium heat. Form meat into eight 4-inch patties. Top 4 patties with 2 tablespoons cheese each, placing cheese in center of patties. Cover with remaining 4 patties; press edges together with fork to seal. Sprinkle burgers with salt and pepper
Transfer burgers to grill and cook 10 to 12 minutes or until internal temperature of burgers reach 160 degrees F, turning occasionally.
Divide buns between 4 plates. Place 2 slices prosciutto on bottom half of each bun and spread top half of each bun with 2 tablespoons mayonnaise mixture. Top prosciutto with burger patties, lettuce and tops of buns.