Baking Powder: For each teaspoon, use ½ teaspoon cream of tartar and ¼ teaspoon baking soda.
Buttermilk: For each cup, place 1 tablespoon lemon juice or vinegar in the bottom of a measuring cup and fill with milk. Let stand 5 minutes.
Cardamom: Use an equal amount of ginger.
Chocolate, unsweetened: For each ounce, use 3 tablespoons unsweetened cocoa and 1 tablespoon melted butter.
Cinnamon: Use ½ the amount of nutmeg.
Cloves: Use double the amount of cinnamon and a little cayenne pepper.
Corn syrup: For each cup of corn syrup, substitute 1 cup granulated sugar and ¼ cup water to a boil and boil 1 minute. Set aside to cool.
Egg: For 1 egg, substitute 2 egg whites or 2 egg yolks or ¼ cup egg substitute.
Flour, cake: For 1 cup of cake flour, substitute ¾ cup flour plus ¼ cup cornstarch.
Ginger: Use an equal amount of cinnamon and a pinch of cayenne pepper.
Half-and-half: For each cup of half-and-half, substitute 1 tablespoon vegetable oil or melted butter and enough whole milk to make a cup.
Honey: For each cup, use 1¼ cups sugar and ¼ cup water.
Molasses: For 1 cup, substitute ½ cup honey, ½ cup brown sugar, and ¼ cup water
Nutmeg: Use ½ the amount of cinnamon and ¼ amount of ginger.
Pumpkin pie spice: For each teaspoon, mix ½ teaspoon cinnamon, ¼ teaspoon ginger, 1/8 teaspoon cloves, and 1/8 teaspoon grated nutmeg.