In large cast iron pot, heat olive oil over medium-high heat and sauté onion and garlic until tender, 4–5 minutes. Add smoked tomatoes, vinegar, cayenne pepper and basil. Stir to combine and simmer for 15–20 minutes. Remove from heat, season with salt and pepper and allow to cool. Once cooled, remove basil and transfer in batches to Vitamix® or blender; blend until smooth. Refrigerate until needed.