Below you'll find substitution suggestions courtesy of the USDA Nutrient Database for Standard Reference


COMMON INGREDIENT SUBSTITUTIONS

ITEMAMOUNTSUBSTITUTION
Allspice1 teaspoon½ teaspoon cinnamon plus ⅛ teaspoon ground cloves
Arrowroot, as a thickener1 teaspoon1 tablespoon flour; or 1 teaspoon cornstarch
Baking powder1 teaspoon¼ teaspoon baking soda plus ¼ teaspoon cornstarch plus ½ teaspoon cream of tartar
Baking soda1 teaspoon4 teaspoons baking powder; or 1 teaspoon potassium bicarbonate and ⅓ teaspoon salt.
Bread crumbs1 cup1 cup cracker crumbs; or 1 cup matzo meal OR 1 cup ground oats
Brown sugar1 cupAdd 1 tablespoon of molasses plus granulated sugar to make 1 cup
Butter, salted1 cup1 cup margarine; or 1 cup shortening plus ½ teaspoon salt; or ⅞ cup vegetable oil plus ½ teaspoon salt
Butter, unsalted1 cup1 cup shortening OR ⅞ cup vegetable oil
Buttermilk1 cup1 tablespoon lemon juice or vinegar plus milk to equal 1 cup; or 1 cup plain yogurt
Chocolate, unsweetened1 ounce3 tablespoons cocoa plus 1 tablespoon unsalted butter (or shortening or vegetable oil)
Cracker crumbs¾ cup1 cup dry bread crumbs; or 1 tablespoon quick-cooking oats (for thickening)
Cream, heavy1 cup¾ cup milk plus ⅓ cup melted butter (this will not whip)
Cream, light1 cup⅞ cup milk plus 3 tablespoons melted, unsalted butter
Cream, sour1 cup⅞ cup buttermilk or plain yogurt plus 3 tablespoons melted, unsalted butter
Cream, whipping1 cup⅔ cup well-chilled evaporated milk, whipped; or 1 cup nonfat dry milk powder whipped with 1 cup ice water
Egg 1 whole (3 tablespoons)2 yolks plus 1 tablespoon cold water; or 3 tablespoons vegetable oil plus 1 tablespoon water (for baking); or 3 tablespoons mayonnaise (for cakes); or  2 ½ tablespoons of powdered egg substitute plus 2 ½ tablespoons water, or ¼ cup liquid egg substitute; or half a banana mashed with ½ teaspoon baking powder
Egg white1 white2 tablespoons meringue powder plus 3 tablespoons water, combined
Flour, all-purpose1 cup1 cup plus 3 tablespoons cake flour (not advised for cookies or quick breads); or 1 cup self-rising flour (omit baking powder and salt from recipe).
Reader suggestion: ⅝ cup potato flour; or 1–¼ cups rye flour or coarsely ground whole-grain flour; or 1 cup cornmeal
Flour, cake1 cup1 cup minus 2 tablespoons sifted all-purpose flour plus 3 tablespoons cornstarch
Flour, self-rising1 cup1 cup all-purpose flour plus 1–½ teaspoons baking powder plus ¼ teaspoon salt
Garlic1 small clove⅛ teaspoon garlic powder or instant minced garlic
Herbs, dried½ to 1 teaspoon1 tablespoon fresh herbs, minced and packed
Honey1 cup1–¼ cups sugar plus ½ cup liquid called for in recipe (such as water or oil); or 1 cup pure maple syrup
Ketchup1 cup1 cup tomato sauce plus ¼ cup sugar plus 3 tablespoons apple cider vinegar plus ½ teaspoon salt plus inch of ground cloves combined; or 1 cup chili sauce
Lemon juice1 teaspoon½ teaspoon vinegar
Lemon, juice and rind1 lemon3 tablespoons bottled lemon juice and 1 teaspoon dried grated rind
Lemon rind, grated1 teaspoon½ teaspoon lemon extract
Mayonnaise1 cup1 cup sour cream or plain yogurt; or 1 cup cottage cheese (pureed)
Milk, skim1 cup⅓ cup instant nonfat dry milk plus ¾ cup water
Milk, to sour1 cup1 tablespoon vinegar or lemon juice plus milk to equal 1 cup. Stir and let stand 5 minutes.
Milk, whole1 cup½ cup evaporated milk plus ½ cup water; or ¾ cup 2 percent milk plus ¼ cup half and half
Molasses1 cup1 cup honey or dark corn syrup
Mustard, dry1 teaspoon1 tablespoon prepared mustard less 1 teaspoon liquid from recipe
Oat bran1 cup1 cup wheat bran or rice bran or wheat germ
Oats, old-fashioned1 cup1 cup steel-cut Irish or Scotch oats
Oil, for baking½ cup½ cup of applesauce (keeps baked goods moist but with less fat)
Onion, chopped1 small1 tablespoon instant minced onion; or 1 teaspoon onion powder; or ¼ cup frozen chopped onion
Quinoa1 cup1 cup millet or couscous (whole wheat cooks faster) or bulgur
Sugar, dark brown1 cup1 cup light brown sugar, packed; or 1 cup granulated sugar plus 2 to 3 tablespoons molasses
Sugar, granulated1 cup1 cup firmly packed brown sugar; or 1–¾ cups confectioners’ sugar (but makes baked goods less crisp); or 1 cup superfine sugar
Sugar, light-brown1 cup1 cup granulated sugar plus 1 to 2 tablespoons molasses; or ½ cup dark-brown sugar plus ½ cup granulated sugar
Sweetened condensed milk1 can (14 oz.)1 cup evaporated milk plus 1-¼ cup granulated sugar. Combine and heat until sugar dissolves.
Tomatoes, canned1 cup½ cup tomato sauce plus ½ cup water; or 1–⅓ cups chopped fresh tomatoes, simmered
Tomato juice1 cup½ cup tomato sauce plus ½ cup water plus dash each salt and sugar; or ¼ cup tomato paste plus ¾ cup water plus salt and sugar, to taste
Tomato ketchup½ cup½ cup tomato sauce plus 2 tablespoons sugar, 1 tablespoon vinegar, and ⅛ teaspoon ground cloves
Tomato puree1 cup½ cup tomato paste plus ½ cup water
Tomato soup1 can (10–¾ oz.)1 cup tomato sauce plus ¼ cup water
Vanilla bean1-inch bean1 teaspoon vanilla extract or substitute bourbon, rum, or whiskey, using two times the amount of vanilla called for in the recipe.
Vinegar1 teaspoon1 teaspoon lemon or lime juice, or 2 teaspoons white wine
Vinegar, apple cidermalt, white wine, or rice vinegar
Vinegar, balsamic1 tablespoon1 tablespoon red- or white-wine vinegar plus ½ teaspoon sugar
Vinegar, red winewhite-wine, sherry, champagne, or balsamic vinegar. 
Vinegar, riceapple cider, champagne, or white-wine vinegar
Vinegar, white wineapple cider, champagne, fruit (raspberry), rice, or red-wine vinegar
Wine1 cup1 cup chicken or beef broth; or 1 cup fruit juice mixed with 2 teaspoons vinegar; or 1 cup water
Yeast1 cake (⅗ oz.)1 package (¼ ounce) or 1 scant tablespoon active dried yeast
Yogurt, plain1 cup1 cup sour cream (thicker; less tart) or buttermilk (thinner; use in baking, dressings, sauces)

SUBSTITUTIONS FOR UNCOMMON INGREDIENTS

Here is a list of substitutions for ingredients that are a little less common or can occasionally be hard to find.

ITEMSUBSTITUTION
Balsamic vinegar—1 tablespoon1 tablespoon red wine vinegar plus ½ teaspoon sugar
Bamboo shootsAsparagus (in fried dishes)
BergamotMint
ChayotesYellow summer squash or zucchini
CilantroParsley (for color only; flavor cannot be duplicated)
Coconut milk2–½ cups water plus 2 cups shredded, unsweetened coconut. Combine and bring to a boil. Remove from heat; cool. Mix in a blender for 2 minutes; strain. Makes about 2 cups.
Delicata squashButternut squash or sweet potato
Green mangoesSour, green cooking apples
Habanero peppers5 jalapeno peppers or serrano peppers
Italian seasoningEqual parts basil, marjoram, oregano, rosemary, sage, and thyme
LemongrassLemon zest (zest from 1 lemon equals 2 stalks lemongrass)
Limes or lime juiceLemons or lemon juice
Lo Mein noodlesEgg noodles
Mascarpone
— 1 cup
3 tablespoons heavy cream plus ¾ cup cream cheese plus 4 tablespoons butter
NeufchatelCream cheese or Boursin
Palm sugarLight brown sugar
Rice winePale, dry sherry or white vermouth
Red peppersEqual amount pimientos
Romano cheeseParmesan cheese
SaffronTurmeric (for color; flavor is different)
ShallotsRed onions or Spanish onions
Shrimp pasteAnchovy paste
Tamarind juice5 parts ketchup to 1 part vinegar