Preheat oven to 350° F. Place frozen meatballs on baking sheet and cook 20-25 minutes, add to a large saucepan with lid, cover meatballs with sauce keep warm over medium heat stirring occasionally. 

Using a second large saucepan heat olive oil over medium heat, add the onions and garlic and cook until translucent and soft (about 3-4 minutes.) Pour in the vegetable stock and bring to a boil. Reduce the heat to a simmer and then while stirring constantly with a whisk, slowly pour in the cornmeal polenta. Continuing to whisk and cook for 5 minutes. Whisk in the ricotta, Parmesan cheese and season with salt and black pepper to taste.

 To plate, divide the polenta into bowls and spoon the meatballs and sauce over top. Serve garnished with additional Parmesan cheese and torn basil leaves.