Add the butter and olive oil to a large pot over medium heat. Add the onion, celery, and garlic. Saute until softened, about 5 minutes.
Transfer the veggies to a blender. Cover and puree until smooth. Then return the puree to the same pot.
Add the tomato sauce and tomato paste and stir to combine.
Add parmesan, basil, oregano, salt, sugar, pepper, bay leaf, and fennel seed and stir everything together. Allow the sauce to simmer on medium-low heat for 30 to 60 minutes.
Remove the bay leaf. Store in an airtight container in the fridge or use immediately on your pizza.