Juicy Lucy Sliders

Instructions

1. Divide beef into twelve portions; shape into balls. Form into patties, each about 1/4-inch thick. Place two provolone cubes into the center of six patties. Top with remaining patties; press meat edges to seal. Season with salt, pepper and garlic salt.
2. Cook two burgers, covered, in a large skillet over medium-high heat for 5 minutes. Flip patties. Add 1 tablespoon water. Cover and cook for 4-6 minutes longer or until a thermometer inserted into patties reads 160ºF. Repeat step with remaining burgers. Keep warm.
3. Meanwhile, spread butter on buns. Toast in a large skillet over medium heat until light golden brown.
4. Combine mayonnaise and sun-dried tomato pesto in a bowl; spread on bun bottoms. Top with burgers and spinach. Replace bun tops.