"True beef suet is the pure pearly, crumbly fat that surrounds beef kidneys. Beef fat from other parts of the animal, though often sold as suet, is not the same thing and should not be used. If possible, order suet from a butcher. Supermarket suet is intended primarily as bird food and may not be genuine or truly fresh."
"Ground or finely chopped beef suet is essential to certain steamed puddings, particularly
Plum Pudding. Because it melts relatively late in the cooking process, after the starch in the batter has begun to set, suet leaves behind thousands of tiny spaces in the pudding, These spaces make the pudding soft and fine grained. Suet also imparts a special richness, without any beefy taste."
"You simply cannot make a good plum pudding with butter or shortening.. It will end up greasy and heavy."
"Buy at least 10 ounces of suet to yield 8 ounces cleaned. Cut away and discard any parts that are reddish or that look dried out, then crumble what remains between your fingers and remove any pieces of tough filament. (A certain amount of the fine, papery filament will remain; don't worry about it.)
Separate the pieces of suet and freeze solid in preparation for chopping. The suet must be chopped to a very fine, crumb-like consistency, but it must not be allowed to melt and become pasty. If you work quickly, you will have no trouble doing this with a large chef's knife. Alternatively, you can grind the suet in a food processor fitted with the metal blade, being careful not to over-process.
Extra beef suet can be sealed in an airtight plastic bag and frozen for up to 6 months."