Sweetbreads a la St. Cloud

This is one of Ranhofer's shorthand entries: the actual cooking lives in the cross-references, and the recipe itself only describes the decoration and the sauce. Read it as an assembly diagram for a braised sweetbread.

• What "studding" meansThe studs are batons of black truffle and cooked red tongue inserted into the surface of the sweetbread with a larding needle or the point of a small knife, so the finished piece shows four dark studs around a red centre. The effect is largely decorative, and the studding is done before braising, while the sweetbread is still firm from pressing.
• Preparing the sweetbreads first"Prepare" points to Ranhofer's general handling of sweetbreads elsewhere in the book: soaking in cold water until no pink remains, brief blanching, refreshing, and peeling off membrane and outer fat. Pressing them flat under a weight was common practice and makes them easier to stud and slice, but the timings here are a modern reconstruction rather than anything this entry specifies.
• The braiseNo. 1554 carries the actual cooking: a white braise, moistened part way up and cooked gently so the sweetbreads stay pale rather than browning. The recipe states no temperature or timing, and the details of the braising bed should be taken from No. 1554 itself. Veal sweetbreads are done when they feel firm and springy through the middle, not soft.
• Allemande sauce is the hingeAllemande is a velouté finished with a liaison of egg yolks and cream, sharpened with lemon. Once the yolks are in it must be held below a simmer — around 180F — and never allowed to boil, or it will break into curds. Add the hot velouté to the yolks in a thin stream, return it to low heat, and strain.
• "A light allemande""Light" here most likely means thinner rather than paler: the sauce slackened, perhaps with a little white stock or strained braising liquid, so it pools around the ring rather than coating it. The text does not spell this out. The sauce-boat holds the same sauce.
• Mushroom puréeNo. 722 supplies the purée; consult it rather than the summary here. Whatever the binding, it wants to be dry enough not to weep, or it will slacken the sauce it sits in -- cook it further rather than adding more binding.
• TrufflesRanhofer means fresh or preserved black truffle, sliced and cut into small uniform pegs. Preserved truffle in jars still works for the studs; truffle oil does not, since the point is the visual contrast.
• Yield and dressingOne veal sweetbread per person, dressed in a ring on a round platter with the purée mounded in the centre. Four sweetbreads make a reasonable course; the sauce needs to be finished at the last minute, so have everything else ready before the yolks go in.
• SourcingAsk a butcher for heart sweetbreads, the plump pair, rather than throat sweetbreads, which are stringier and will not press into a neat shape. They are highly perishable -- use within a day of purchase.