In a large saute pan, heat the olive oil and butter over high heat. Add chopped onions and celery and saute until they are soft and beginning to turn golden.
Add garlic and stir constantly for 2 more minutes to let the garlic do its thing without burning.
Turn heat to medium and add dried oregano, salt, pepper and sugar. Stir and let cook for another minute.
Add crushed tomatoes and give the bottom a good scrape to deglaze your pan. Add water and stir to combine everything. The sauce will get thicker from here, so if it is already too thick for you, then add an additional 1/4 cup water.
Turn heat to low and add fresh basil leaves. Let the mixture simmer for 10 minutes stirring occasionally. You can simmer for as long as you want and the sauce will continue to get thicker and more flavorful. Serve over pasta and enjoy!