In the raw-food world, where it originated, it's used in lots of desserts. When you cook with it, though, it can be so much more—from cheese filling in ravioli to heavy cream in soups. It can be stored 2 to 3 days in the refrigerator and can be frozen for up to 6 months (although after it's defrosted it can be a bit lumpy, so it's good to give it a spin in the blender to smooth it out before using it).
The trick when making cashew cream is to use raw cashews. They have no flavor of their own; they're just a vessel for fat and creaminess. (It's the roasting that brings out the familiar sweetness in cashews.) Because it has a nice fat content, cashew cream reduces in a pan even faster than heavy cream. (Soy milk, which some people use in vegan cooking, has no fat, so it doesn't reduce into a thick sauce—it's really not an alternative.)
Drain the cashews and rinse under cold water. Place in a blender with enough fresh cold water to cover them by 1 inch. Blend on high for several minutes until very smooth. (If you're not using a professional high-speed blender such as a Vita-Mix, which creates an ultra-smooth cream, strain the cashew cream through a fine-mesh sieve.)
To make thick cashew cream, which some of the recipes in this book call for, simply reduce the amount of water in the blender, so that the water just covers the cashews.