You can make small adjustments to any recipe to make it more nutritious. To thicken soups and sauces, in place of cream, use puréed or shredded potato, or puréed cooked dried beans. Citrus juice or a flavored vinegar can stand in for most of the oil in a marinade. You can also forgo butter–rich sauces on vegetables and add a sprinkling of lemon, lime, or orange zest or a scattering of chopped toasted nuts. Low–fat or non–fat yogurt is often a great substitute for sour cream, and buttermilk for cream when baking. Instead of a butter–rich pastry pie crust, try a graham cracker or gingersnap cookie crust, or a meringue shell.