Step 1 In a large, heavy-bottomed pot, heat the olive oil and butter over medium heat. Add the onion, shallots, carrot, celery and fennel and cook until softened, stirring occasionally, about 5 minutes. Stir in the minced garlic and continue to cook for 1 minute until aromatic.
Step 2 Add the diced tomatoes with their juices, along with the lemon juice, sugar, paprika, gin and 1 1/2 teaspoons salt. Cook, stirring frequently, until the tomato liquid reduces and the mixture has thickened slightly, 10 to 12 minutes. Cool slightly.
Step 3Transfer the vegetables, in batches, to a blender jar and puree until smooth, then return to the pot. Add the broth, one cup at a time, until the soup reaches desired consistency, stirring to thoroughly combine.
Step 4Bring the soup to a gentle simmer over medium heat, stirring frequently. Add the cream if desired and adjust the seasoning to taste with salt and black pepper. Garnish each serving with basil.