Preheat oven to 375 degrees Fahrenheit.

In a small mixing bowl, combine ricotta cheese, Parmesan cheese, and egg. Mix until well combined.

Spread a thin layer of marinara sauce in the bottom of a baking dish and place meatballs in the baking dish.

Spoon a dollop of the ricotta mixture onto each meatball, then pour the remaining marinara sauce over the meatballs.

Sprinkle shredded mozzarella cheese over the sauce, cover with foil, and bake for 25 minutes.

Remove foil and bake for an additional 10-15 minutes or until cheese is melted and bubbly.

Serve with baguettes.