Bring a large pot of salted water to a boil. Add the bowtie pasta and cook according to package instructions until al dente. Drain and set aside, reserving 1 cup of the pasta water.

In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook until it’s translucent, about 3-4 minutes. Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Pour in the crushed tomatoes, and add dried oregano, red pepper flakes, salt, and pepper. Let it simmer for about 5-7 minutes to allow the flavors to meld together.

Stir in the cooked pasta and ricotta cheese. If the mixture looks dry, add a bit of the reserved pasta water until you achieve your desired consistency. Mix everything together over low heat for 2-3 minutes.

Sprinkle the mozzarella and Parmesan cheese over the pasta and stir gently until melted and combined.

Spoon into bowls or a large serving dish. Garnish with fresh basil leaves if using. Enjoy your creamy Bowtie Pasta Ziti!