Chefs didn't embrace vegetable puree-based sauces simply because they're light, but because they're quick, easy, and malleable. Cooked purees like carrot, garlic, onion, fennel, and parsnip can be taken in myriad directions by changing up fat and acid choices, and by finishing with various accents. For instance, carrot puree pairs with walnut oil, sherry vinegar, and tarragon as it does with rice vinegar, ginger, and a grapeseed/sesame oil blend. The point of this recipe is to help you understand the functional building blocks of his vinaigrette: Oil means virtually any culinary oil. For vinegar, any pleasantly acidic liquid will do. For the puree, just make sure it's not fibrous or overly "seedy," and you're good to play. Here, we build on the Charred Tomato Passata recipe.