In a large pot, add the rigatoni pasta, minced garlic, oregano, and a colorful assortment of chopped vegetables such as onions, squash, mushrooms, and spinach. Pour in your chosen marinara sauce and stir well to coat everything evenly.

Pour in enough water or vegetable broth to cover the pasta and vegetables, following the pasta's package instructions, typically about 4 cups.

Place the pot on medium-high heat and bring to a rolling boil, which should take about 5–7 minutes.

Cover the pot and let it simmer gently for the time indicated on the pasta package, usually around 10–12 minutes.

After cooking, taste a piece of pasta for doneness. It should be tender yet slightly firm (al dente). Season with salt and pepper as desired.

Remove from heat, let it sit for a minute, and serve hot, garnished with crushed red pepper, fresh herbs, or nutritional yeast.