1. Place a rack in upper-middle of oven and heat broiler.
2. Combine ground beef and pork in a large bowl and mix lightly with a fork until just combined. Add panko, Parmesan, water, egg, parsley, garlic, salt, pepper, and oregano and continue to mix until just incorporated (do not overmix).
3. Form mixture into 12 balls about 2 1/2" in diameter and place on a foil-lined baking sheet. Broil meatballs until browned, 10 to 12 minutes, flipping once halfway through.
4. Combine marinara sauce and red pepper flakes in a Dutch oven and bring to a simmer over medium heat. Reduce heat to medium-low, add meatballs, and partially cover pot. Simmer meatballs 10 minutes, stirring occasionally. Place rolls cut side up on a baking sheet and broil until lightly browned, about 2 minutes.
5. To assemble sliders, spoon a small amount of sauce on each roll bottom and top with a meatball, more sauce, and a piece of provolone. Top with pepper rings, more parsley, and roll tops.
Source: Hannaford fresh Magazine, January - February 2019