In a large pot, heat butter and olive oil over medium heat. Add in the finely diced onion and minced garlic and cook for 5 minutes or until soft.
Add in the crushed tomatoes, water, salt, sugar, black pepper, red pepper flakes, dried oregano, tomato paste, and basil paste. Give the ingredients a good stir, bring to a boil, then simmer uncovered for 20 minutes or until the sauce reaches your desired consistency.
I blend about 1 cup of the marinara sauce and mix it back with the rest of the marinara. you could do that using a hand blender before serving.
Serve this quick flavorful marinara with pasta or anything you use marinara with.
This marinara sauce can be stored in an airtight container in the fridge for up to 3 days.