Usefull list of common substitutions

Baking powder 1 t = 1/4 t baking soda+ 1/2 t cream of tartar
Bread crumbs 1 cup = 3/4 c crumbled crackers
Buttermilk 1 cup = 1 cup soy milk with 1 T lemon (let stand 5 minutes)
Cake flour 1 cup = 1 cup sifted all purpose flour minus 2 T
Chocolate 1 square ( 1 ounce) = 3 T cocoa powder and 1T EB
Corn starch (thickening) 1 T = 2 T AP flour
Corn Syrup (not for baking) 1 cup = 1 1/4 sugar plus 1/3 water
Fresh herbs 1 T = 1 t dried or 2/3 t ground
honey 1 cup = 1 1/4 cup sugar and 1/4 water
Ketchup or chili sauce 1/2 cup = 1/2 cup tomato sauce plus 2 T sugar, 1 T vinegar and 1/8 t ground clove
Lemon juice 1 teaspoon = 1/2 teaspoon vinegar
Hot sauce 3 to 4 drops = 1/8 t cayenne pepper
Mustard (wet) 1 T = 1 t dried mustard
Oregano dried 1 t = 1 t dried marjoram
Tomato paste 1 T = 1 T ketchup
Vinegar 1 t = 2 t lemon juice