Render it down to make tallow: cut into small pieces, melt slowly over low heat, strain through cheesecloth, and store in a sealed jar. Use the rendered tallow for cooking.
Use raw grated suet in British-style puddings, dumplings, and pastry, it gives a flaky, rich texture that butter can't match.
Beef suet is the firm fat from around the kidneys, the highest-quality fat on the animal with a neutral flavor and high melting point. It renders into very clean, white tallow.
Keep refrigerated for up to 2 weeks, or freeze for up to 12 months. Thaw in the refrigerator overnight before using. Use fresh or render into tallow for long-term storage.