My wife has been using beans instead of fat in baking for about a year now. The taste and textures amazes most people when we tell them what is used. The cake cooks just a bit faster than normal, so be sure and watch close the first time you cook with them. The cake stays moist longer.
There are two easy ways to replace fat with beans in most baking.
1. Simply cover beans with water and cook until very soft. Mash until the beans are about the consistency of shortening. You can use a blender. Replace the fat in recipes cup for cup. For example if a recipe calls for 1-cup margarine—use 1-cup mashed beans. Liquid may be added to adjust the consistency. Mashed beans do not keep long in the fridge, so use them or freeze them.
2. Grind the beans in your wheat grinder to make bean flour. Store the flour in an airtight container. Replace the fat in recipes cup for cup as above. You will need to add extra liquid since the ground beans will be part of the dry ingredients.
Other types of beans will work, including canned beans. The type of bean will have a slight effect on the taste. White beans give it a slight vanilla taste. The color of the bean should match the color of what you are baking. For instants use black beans for chocolate cake.