Instructions

1. Gently knead 1/4 cup of pesto into the ground chuck and sirloin. Form the mixture into six patties.
2. Oil grill grates, and heat gas or charcoal grill to medium-high heat. Grill the burgers for 3 minutes. Flip the burgers, top with mozzarella slices and close the grill. Cook for 3-5 minutes longer for medium-rare burgers.
3. Grill the buns until lightly toasted, then divide the remaining pesto on the bottom of the buns. Top with the burger and tomatoes. Close the burgers and serve.