The monk fruit, siraitia grosvenorii, is native to China and parts of Thailand. The primary use for this fruit in the U.S. is for a very, almost no-cal sweetener. The sweetener is made from the juice and pulp of the fruit. In China, the fruit pulp is eaten, and the thin skin is used to make tea.
Monk fruit is 100-250 times sweeter than granulated sugar, so keep this in mind when you start using it in place of regular table sugar. Sugar producer, In The Raw, suggests using their monk fruit sugar in beverages, added to smoothies, or even to sweeten your yogurt or to top your cereal.
Sugar plays an essential roll in baking, including adding flavor, helping baked goods to brown, and adding volume. In The Raw suggests experimenting with your favorite recipes and substitute not more than 1/2 of table sugar with monk fruit sweetener. This sweetener is heat stable so you can bake or cook with it.
If you don't have monk fruit sweetener, you can substitute another low-calorie sweetener, such as Stevia or Splenda. Substituting sweeteners can be a little tricky and involves some trial and error. For best results, use recipes that written to use that specific sweetener.
If your recipe calls for Stevia, but you want to use Monk Fruit, you need to know what form of Stevia the recipe calls for. For example, is it a liquid sweetener where a couple of drops equals a tablespoon of sugar or powder that is a 1:1 substitute for sugar? Unfortunately, recipes are not always forthcoming with the details about the sweetener they are suggesting. Once you know each sweetener equivalents, you can match the amounts indicated by the recipe. By equivalents, I mean, how much of each sweetener does it take to equal 1 tablespoon of sugar?
Most likely, you won't find the fruit in your local grocery store, although you may find them if you have A Chinese or Thai market in your area. Otherwise, you can purchase monk fruit paste or monk fruit sugar in many well-stocked markets such as Whole Foods. You can also buy them online at Amazon.com: Monk fruit puree and sugar.