Heat a large saucepan over medium heat, add Butter (1 tablespoon), and enough Extra-Virgin Olive Oil (to taste) to coat the bottom of the pan.
Lower the heat to medium-low and add the Yellow Onion (1) and Water (2 tablespoon). Cook the onion low and slow for about 15 minutes until the onions are very soft, but not brown. If the onions start to brown or caramelize, lower the heat or add a little more water one tablespoon at a time.
Once the onions are cooked, add the Vodka (1/4 cup), Calabrian Chili Paste (1 tablespoon), and Crushed Red Pepper Flakes (1/2 teaspoon). Turn the heat to medium, and mix everything together. Cook until the vodka reduces by half (about 2 to 5 minutes).
Add the San Marzano Tomatoes (2 can). Stir until everything is combined, breaking the tomatoes with the back of your spoon. Season with salt and pepper, and bring the sauce to a boil. Once boiling, lower the heat to medium-low and let the sauce simmer for at least 30 minutes, partially covered.
Take the sauce off the heat, and using a hand blender (or regular blender if you don’t own a hand blender), blend the sauce until it is nice and smooth.
Once blended, turn the heat to low and slowly stir in the Heavy Cream (1 1/2 cup), the remaining tablespoon of Butter (1 tablespoon), and a nice handful of Parmesan Cheese (to taste). Taste and adjust seasoning as needed.