In a large pot, heat oil over medium heat until shimmering. Add sausage and brown, breaking up into small chunks, until no longer pink, about 5 minutes. Drain any excess fat. Add onion, garlic, and red pepper flakes, and saute for 1 minutes. Stir in tomato paste and cook until it turns a rusty brown, about 5 minutes.
Add tomatoes with juice, stock and bay leaves; bring to a boil. Reduce heat and simmer for about 30 minutes to blend the falvors. Add past, increase heat to medium-high and boil until al dente, about 8 minutes. Discard bay leaves. Stir in basil and season with salt and pepper to taste.
Preheat broiler and place oven safe bowls on a baking sheet.
Scoop a heaping spoonful of ricotta into each bowl. Ladle soup into bowls and top each bowl with Parmesan and mozzarella cheese. Place in broiler with oven door cracked for 3-5 minutes until cheese browns.
Go to full version of