These substitutions should only be used if absolutely necessary.  Whenever possible, you should use the ingredients called for in a recipe.

• 1 tablespoon cornstarch  =  2 tablespoons flour:  This is good to use for making gravy or for making any liquid thicker.  Whether using cornstarch or flour to thicken, make sure to mix it with cold water until you have it smooth before you add it to whatever you are thickening.  If you don’t, you will have lumps.
• 1 cup sifted all purpose flour  =  1 cup + 2 tablespoons sifted cake flour
• 1 square unsweetened baking chocolate (ounce)  =  3 tablespoons cocoa +1 tablespoon butter or margaring
• 1 teaspoon baking powder  =  1/4 teaspoon baking soda + 1/2 teaspoon cream of tartar (you’ll find cream of tartar in the spice aisle at the grocery store.  But if you need to buy cream of tartar to use this substitution, you might as well buy baking powder instead while you are at the store!
• 1 cup milk  =  1/2 cup evaporated milk + 1/2 cup water (it’s a good idea to keep a couple of cans of evaporated milk on hand to use in various recipes.)
• 1 cup buttermilk  =  1 cup milk + 1 tablespoon white vinegar or lemon juice (O.K. I know this sounds disgusting, but I use this all the time for making biscuits.  Your biscuits will taste better when made with buttermilk, but who keeps buttermilk in the fridge any more?  After you add the vinegar to the milk, let it sit for 5 minutes to “curdle” the milk.  Then add to your recipe as usual.
• 1 cup sour cream  =  1 cup plain unflavored yogurt (yogurt is a healthier alternative to sour cream)
• 1 cup molasses  =  1 cup honey 
• 1 cup honey  =  3/4 cup granulated sugar + 1/4 cup liquid
• 1 cup brown sugar (firmly packed)  =  1 cup granulated sugar
• 2 large eggs  =  3 small eggs
• 1 whole egg  =  2 egg yolks (for custards)