Cut cheesecloth into two 3-foot pieces. Wrap the roast in the first piece, rotate 90 degrees, then wrap in the second. Tie with twine.

Set the wrapped roast on a rack over a sheet pan and refrigerate uncovered for 4 to 5 days.

Unwrap the roast about 90 minutes before cooking. Rub 2 tablespoons of tallow into the surface, then pack on salt and pepper.

Insert a probe thermometer horizontally through the fat cap, angling up into the eye muscle at least 3 inches deep. Set the alarm to 118°F.

Roast at 250°F on a bottom-third rack for roughly one hour per rib bone, until the alarm sounds.

Remove the roast and rest it uncovered in a warm spot, leaving the probe in place.

Heat an empty skillet in a 400°F oven. Mix 4 tablespoons of pan drippings into the pudding batter, then add 2 tablespoons to the hot skillet.

Pour in the batter and bake about 30 minutes until puffed and golden brown.

Pull the probe from the meat, raise the oven to 550°F, and roast the beef for 10 minutes to build a dark crust.