01 -
Set the oven to 400°F and line a sheet pan with parchment paper.
02 -
In a large bowl, whisk together the egg, breadcrumbs, Parmesan, Italian seasoning, minced onion, garlic powder, salt, pepper, and water. Add ground beef and turkey, mixing gently by hand until evenly combined.
03 -
Divide the mixture into 15 equal portions on a clean surface. With dampened hands or oiled with cooking spray, roll each portion into a ball and place on the prepared baking sheet.
04 -
Bake the meatballs for 15-20 minutes until fully cooked through.
05 -
When meatballs have about 5 minutes remaining, pour pasta sauce into a medium saucepan and warm over medium-low heat, reducing to low if it begins to bubble. Stir occasionally.
06 -
Once baked, transfer meatballs to the warmed sauce and coat evenly. Portion approximately 3 meatballs with ¼ cup sauce per sandwich.
07 -
Move the oven rack to the top position and change setting to broil. Replace parchment paper with aluminum foil on the baking sheet and arrange open buns. Fill each bun with meatballs and sauce, then sprinkle 2 tablespoons shredded Mozzarella over the top.
08 -
Broil sandwiches for approximately 2 minutes until cheese melts and bun tops toast lightly. Monitor closely to prevent burning.