Toss tomatoes in 2 tablespoons of olive oil then season with salt and pepper and place on a baking sheet with the cut side up. Cook for around 35 to 40 minutes then remove from oven.
When the tomatoes are around halfway through cooking, bring a large pot of water to a boil. Add pasta and cook until al dente according to the package instructions then drain.
Heat remaining 2 tablespoons of olive oil in a large pot or dutch oven over medium heat then add onion and cook until softened, around 3-4 minutes. Add garlic and cook for 30-45 seconds, stirring constantly, until fragrant. Add tomato paste and cook for another minute, again stirring constantly, until slightly darkened. Add the roasted tomatoes and break them up with a wooden spoon. Stir in the basil and cook for another 2-3 minutes. Season with additional salt and pepper to taste.
Add the cooked pasta to the sauce and stir. Cook for another minute then portion into bowls. Top with a scoop of ricotta cheese and shredded Parmesan before serving.
Notes
If you prefer a smoother sauce puree finished sauce in a blender or process through a food mill then return to the pot before adding the pasta.