Almond flour is made from finely ground blanched almonds. The only thing that distinguishes almond flour from almond meal is that the meal is more coarse. In fact some brands such as Bob's Red Mill refers to the product as almond flour/meal. They can typically be used interchangeably in quick breads, muffins or pancakes.
Almond flour may be made of blanched almonds or almonds with skins on; check the product label if you require one product over the other. See the recipe below to make your own.
We use almond flour in one of our favorite easy dessert recipes; Almond Sunshine Cake.
If you don't have almond flour you can substitute almond meal (coarser texture)
OR> Make your own, see instructions on this page.
Some people can't eat nut flours. An option is to use coconut flour as an alternative to almond flour. While both have a more granular texture than most grain flours, coconut flour absorbs moisture at a high rate than does almond flour. This will require some experimentation. Try using 1/4 cup of coconut flour to replace 1 cup of almond flour. Then either add an extra egg to the recipe OR double the amount of liquid called for (or you may need to do both. Additionally coconut flour may change the flavor in your recipe.
Don't forget it may be easier to search for a recipe that was designed to use alternative flours rather than spending a lot of time trying to adapt a recipe that was meant to use a different key ingredient.
Substituting Coconut Flour for Almond Flour In Paleo Recipes - Tips for substituting coconut flour for almond flour. Baking With Almond Flour - King Arthur has a great guide with tips and pictures showing you how to substitute almond flour for all-purpose flour and the affects on baked goods.
Ground almonds. Some brands may contain preservatives
Nut flour has a high oil content and will go rancid rather quickly. It is best to make in a batch for your specific recipe. David Lebovitz suggests using some of the flour or sugar called for in the recipe when blending the flour. This helps to prevent the flour from being heated and becoming oily.
Place nuts and about 2 tablespoons of the flour or sugar in a blender jar with a sharp blade. This is probably not the best job for your twenty year old blender if you've never changed out the blade. Alternately you can use a food processor.
Just pulse the blender or food processor on and off until the nuts are ground to an even consistency. Don't expect a perfectly refined texture because nuts don't grind very evenly.
If you have excess flour it should be stored in the refrigerator. Place the flour in a jar with a tight fitting lid.