Slow Cooker Tomato Basil Parmesan Soup. Best homemade tomato soup recipe I've tried yet! Used 2 tsp dried basil instead of fresh, whole milk instead of cream, and 1.5 cups cheese. Added 3 carrots, 1 Tbs. sugar, and blended it twice, once before the roux, and once about 10 minutes before serving after the cheese had melted. So delicious!