Roasted Pepper-Stuffed Burgers

In a large bowl combine ground beef, vinegar, the 1/2 teaspoon black pepper, and the 1/4 teaspoon salt. Working on waxed paper, shape mixture into twelve 4-inch-diameter patties.

Place cheese and roasted peppers on the center of six of the patties. Top with the remaining six patties; pinch edges together to seal.

Place waxed paper with patties on a baking sheet and freeze about 1 hour or until firm. Layer frozen patties between sheets of waxed paper in a freezer container; seal and freeze for up to 1 month.

To serve, thaw in a single layer in the refrigerator overnight. Sprinkle patties with additional salt and black pepper.

For a charcoal or gas grill, place patties on the grill rack directly over medium-high heat. Cover and grill for 10 to 12 minutes or until patties are done (160°F), turning once halfway through grilling.

In a small bowl combine mayonnaise and pesto. Spread cut sides of buns with mayonnaise mixture. Fill buns with burgers and basil leaves.