Step 1

Trim the fat off of the kidney and discard it. Once you have the kidneys and are ready to cook them, you must first rid them of the thick, white sections of fat. Put the kidney on a cutting board and use a sharp kitchen knife to trim off these sections.Instead of discarding the fat, you could set it aside to render it down to use with other recipes. Rendering fat takes several hours—you can do it in a slow cooker or on the stovetop. Put the fat into your slow cooked or into a pan on the stovetop, turn the heat to low, and stir and check it every 20 minutes. It’s ready once the fat has liquidized. Strain the fat to remove any bits of cracklings or gristle, and store it on the counter in a covered container, like a mason jar.

Step 2

Remove the grisly membrane from the center of the kidney. Slice through the kidney vertically (retaining the kidney shape) to access the tough, white membrane. Use your knife to trim the organ meat from around the membrane to remove it. Put the membrane to the side to discard it later.The membrane is especially tough and hard to cut through, which is why it’s recommended to remove it before cooking the kidneys.

Step 3

Cut the kidney into strips or small pieces, depending on your recipe. Try your best to cut similar sized pieces to help them cook at the same rate. Strips of kidney are generally used for a quick sauté and diced kidney is usually used in different stews.Kidney can be tough to cut through, so using a sharp kitchen knife is important. If you don’t have a sharp knife, consider buying one from a home goods store or even purchasing a whetstone or honing rod to sharpen your knives at home.

Step 4

Store raw kidney in the fridge for 2 days or in the freezer for 4 months. If storing it in the fridge, keep the kidneys in the original packaging or in a clean, air-tight container until you’re ready to prep it for your recipe. If freezing the kidneys, keep them in their original casing and wrap that in foil or plastic wrap.Write the purchase and use-by dates on the package when freezing kidneys to help you remember how long they will be good for.