Start by combining the ground beef with the beaten egg, parmesan, garlic, breadcrumbs, salt, pepper, and red pepper flakes. Mix until smooth.
Divide the mixture into 1.5-inch balls using a cookie scoop or a spoon. Roll them into balls and place them on a baking sheet; this should yield 12-14 meatballs.
Bake in a preheated oven at 400°F for 20-25 minutes, or until they are no longer pink in the middle. Flip halfway through to prevent the bottoms from burning. Toss the cooked meatballs in a bit of marinara sauce, just enough to coat.
Assemble the Meatball Sliders on Hawaiian Rolls
Use a knife to cut a 1-inch circle out of the center tops of each roll. Remove the circle of bread and discard. Use the bottom of a shot glass to work into the opening to make room for the meatballs (see photos).
Combine 2 teaspoons of garlic with 4 tablespoons of melted butter and the parsley. Use a basting brush to brush it over the tops and the insides of each roll.
Bake in a 400-degree oven for 5 minutes or until the tops start to turn golden brown.
Add a generous pinch of mozzarella into each crevice, pushing it down. Top it with a spoonful of marinara.
Stuff each roll with one meatball, and wedge them down into the hole.
Top the meatballs with another pinch of mozzarella and return them to the oven until the cheese has melted.
Brush a final coat of garlic butter over the tops of the rolls and serve with a drizzle of hot honey over each one.