Since we live in the middle of nowhere, if I'm out of an ingredient, just running to the store isn't an option. Plus I do a lot of cooking during Goose's naptime, so I couldn't go anywhere even if I wanted! Enter The Cook's Thesaurus.
I have used it for a huge variety of things - what the proportion of ingredients is for self-rising flour (since I don't buy it), how much molasses and white sugar makes brown sugar, what cuts of beef are similar to swap out in recipes, and the list goes on. I've found it especially helpful when a recipe calls for a rather exotic ingredient that I can't find or is quite expensive. Often I can discover a more common, cheaper alternative, or I can confirm that I can leave it out with little ill effects.
Categories it covers include:
Vegetables * Fruits * Dairy * Flavorings * Liquids * Grains * Grain Products * Baked Goods * Legumes and Nuts * Meats * Fish * Vegetarian * Baking Supplies * Fats & Oils * Accompaniments * Equipment * Miscellaneous
There is also a search box in case you're not quite sure where your ingredient falls. I've used this site a LOT and have never been let down!
Interestingly, I've found there are two web addresses that both point to The Cook's Thesaurus. They are http://www.switcheroo.com/ and http://www.foodsubs.com/. I usually type in the switcheroo one because I can remember it more easily.
Happy substituting! For more kitchen tips, visit Tammy's Recipes.