Add the oil to a pan on medium-high heat and cook the onions and garlic until deeply caramelized.
Mix in tomato sauce, tomato paste, red pepper flakes, dried basil and oregano. Bring to a simmer for 5 minutes.
Add pre-cooked meatballs and coat them with sauce. Remove sauce from heat.
Roll out three rectangles of puff pastry. One should be 16-inches (41 cm) long, one 22-inches (56 cm) long and the third, 28-inches (71 cm) long. All three should be about 6-inches (15 cm) wide.
Sprinkle the shredded mozzarella cheese in a line across the bottom of each strip, then place meatballs on top in a line about 1-inch (2 cm) apart from each other.
Roll pastry over the meatballs. Then take the smallest roll and wrap it around a small oven safe bowl placed on top of a baking sheet. Make sure the ends of the pastry meet and pat together to connect.
Take a knife and press down the puff pastry between each meatball creating a small opening on either side of the puff pastry. Make a small cut between each meatball just below the top of the puff pastry so that the roll is still connected.
Repeat this step again with the medium roll and largest roll, wrapping them around each other.
Add marinara sauce to the oven safe bowl.
Brush egg wash over the entire ring and sprinkle the shredded parmesan cheese on top. Cover sauce with foil.