I liked Sherry's Pantry List so much that I thought an "Emergency Substitution" list would also be handy.
1-tsp Apple or Pumpkin Pie Spice = 1/2 tsp cinnamon, 1/4 tsp nutmeg, 1/8 tsp each allspice and cardamom
1-tsp Baking Powder = 1/4 tsp baking soda plus 1/2 tsp cream of tartar
1-cup Buttermilk = 1 tbsp vinegar or lemon juice plus milk to make one cup (my all time favorite)
1 square (1 oz) Unsweetened Chocolate = 3 tbsps unsweetened cocoa plus 1 tbsp shortening or margarine
2 oz Semi-sweet Chocolate = 1/3 cup semi-sweet chocolate chips
1/2 cup Corn Syrup = 1/2 cup sugar plus 2 tbsps liquid
1-tbsp Cornstarch = 2 tbsps flour or 1-1/3 tbsps quick-cooking tapioca (used as thickener)
1-cup Heavy Cream (for baking, not whipping) = 3/4 cup whole milk plus 1/4 cup butter
1-cup Light Cream = 7/8 cup milk plus 3 tbsps butter
1-cup Sweetened Whipped Cream = 4-1/2 oz pkg frozen whipped topping or 1 envelope whipped topping mix prepared as directed on package
1 Egg = 2 egg yolks (in baking, add 1 tablespoon water)
1-cup Cake Flour = 7/8 cup all purpose flour plus 2 tbsps cornstarch
1-cup Honey = 1-1/4 cups sugar plus 1/4 cup liquid
1-tsp Lemon or Orange Peel = 1/2 tsp dried peel
1-cup Whole Milk = 1/2 cup evaporated milk plus 1/2 cup water
(OR)
1-cup Whole Milk = 1 cup skim milk or reconstituted nonfat dry milk plus 2 tsps butter
1-pkg Active Dry Yeast = 1 tbsp dry or 1 cake compressed yeast
Hopefully this list will be helpful for you.