1. Preheat your oven to 400 degrees.

2. Heat a large saucepan over medium heat and add olive oil. Once the oil is hot, add the garlic and cook for 45 seconds. Add the sweet Italian sausage, breaking it up with a spoon, and cook until browned.

3. Pour in the San Marzano tomatoes, basil stalks, chili flakes, and salt. Blend briefly with an immersion blender if desired. Bring the sauce to a simmer and let it cook for 15 minutes, stirring occasionally.

4. In a separate pot, bring a large amount of salted water to a boil. Cook the ravioli according to the package directions, aiming for al dente. Drain the cooked ravioli.

5. Assemble the lasagna: In a baking dish, layer half of the cooked ravioli, followed by half of the sweet sausage marinara sauce, and half of the grated mozzarella. Repeat the layers.

6. Sprinkle oregano and chili flakes over the top, and drizzle with olive oil.

7. Bake for 10 minutes or until the cheese has completely melted and the lasagna is heated through.

8. Garnish with fresh basil before serving.