Here are the best appetizers for Valentine's Day:Classic French Onion Soup, Spinach and Goat Cheese Crostini, Strawberry and Feta Salad, Cremini Carpaccio, Cauliflower Bisque with Brown Butter Croutons, Prosciutto, Brie and Apricot Crostini, and Caramelized Pancetta and Fennel Salad.