This is the main course of choice for my New Year's Eve dinners because it's got everything going for it in the party-food department. It's wonderfully satisfying, elegant, universally appreciated (among carnivores, of course), expandable -- you can make it for twenty as easily as you can for two -- and ninety percent do-aheadable, so you need to be away from the action for only a few minutes just before serving.
The dish is a pared-down, luxury edition of pot-au-feu, the traditional one-pot meal that usually includes several cuts of meat cooked in bouillon. Here you've got just one piece of meat, a fillet of beef, tied with a length of kitchen twine that's got a tail long enough to grab, so that you can pull the beef from the broth and rightly call the dish "beef on a string." This version also has a handful of root vegetables that poach in the bouillon, which is made from bones, vegetables, and, yes, a couple of bouillon cubes. The bouillon is prepared ahead, days ahead if you can manage it, and the vegetables can also be made ahead. At serving time, all you've got to do is poach the meat lightly and gently. And there's never a need to worry about whether guests want their meat rare or well-done: you poach the beef until rare, let it rest, and then, at serving time, pour hot bouillon around the beef for the rare-lovers, or over it, to cook it a bit more, for those who like their meat better done.
Traditionally the bouillon is served as a first course and the meat and vegetables as the main, but I like to serve slices of the beef in shallow soup plates surrounded by the vegetables and finished with a small ladleful of broth. Using just a bit of the bouillon moistens the dish perfectly and gives it a lovely look, while leaving some to be turned into soup the next day. Actually, speaking about holding back, you might hope for leftover beef as well.
If you want to multiply the number of servings, keep the same amount of bouillon but double the amount of beef to serve 12; to serve even more (I've made this for a dinner party of 26), you should double the bouillon as well, or poach the beef in batches.
If your beef isn't already tied crosswise at intervals, do this at home using kitchen twine. The crosswise ties will hold it in shape while it poaches. To make the traditional string that gives this dish its name, tie the beef lengthwise -- you can tuck this lengthwise string under the knots made by the crosswise strings -- and leave a long piece of the twine free. You'll use this string to pull the beef out of the broth.
To make the bouillon: Gather together the parsley, thyme, and bay leaves, tuck them between the celery stalks, and tie up the bundle with kitchen string.
Put a large soup pot over medium-high heat and add the oil. Drop in the bones, oxtail, and onions (if you can get everything in without crowding the pot, go for it; if not, do this in batches), sprinkle over the sugar, and brown the bones and onions, stirring as needed. When all the ingredients are as deeply browned as you can get them -- even blackened -- transfer to a bowl, and pour out and discard the fat.
Put the pot back over medium heat and, standing away, pour a cup or two of water into the pot. Using a wooden or metal spoon, scrape up all the goop that formed on the bottom of the pot, a satisfying job, since you get all the color and flavor from the sticky bits and the scraping does a good job of cleaning the pot too. Pour in 4-1/2 quarts water and toss in all the remaining ingredients, including the celery bundle, bones, oxtail, and onions. Bring to a boil, skimming off the scum that bubbles to the top, then lower the heat to a simmer, and cook the bouillon, uncovered, skimming often, for 1 hour.
Strain the bouillon into a bowl and discard the solids -- they've done their job. (The bouillon can be cooled and refrigerated for up to 3 days or frozen for up to 2 months. Once the bouillon is cooled, skim off any fat -- it will have floated to the top.)
To cook the vegetables and beef: Return the bouillon to the pot and bring it to a boil. Lower the heat to a simmer and add the potatoes, turnips, carrots, and celery root. After 10 minutes, add the leeks and shallots and cook for 10 minutes more. Check that the vegetables are cooked and, when they are tender, using a slotted spoon, lift them out of the bouillon and into a large bowl. Cover and set aside while you poach the beef. (The vegetables can be cooked a few hours ahead, moistened with a little bouillon, covered, and refrigerated until you're ready for them.)
Drop the beef into the simmering bouillon, keeping the string out of the broth (you can tie it to the pot's handle) and poach for 15 minutes -- it will be very rare in the center. Pull the beef from the pot using the string; transfer it to a plate, cover with foil, and allow to rest for 5 to 10 minutes. (If you want the beef more well done, you can poach it longer or, better yet, pour some of the hot broth over it at serving time.)
Meanwhile, reheat the vegetables in the bouillon. Cut the beef into slices about 1/4 to 1/2 inch thick. For each portion, put a slice or two of beef in the center of a shallow soup plate, surround it with some poached vegetables, and moisten with bouillon. Have fleur de sel, Dijon and grainy mustard, horseradish, and a peppermill on the table so your guests can season their own dishes.
I like to use shallow soup plates for this dish and arrange them in the kitchen. Carve the beef so the slices are 1/4 to 1/2 inch thick and put a slice or two in each plate. Add the vegetables and ladle a little hot broth either around the meat or, for those who like their meat more well done, over it. Bring the plates to the table and let your guests season their servings to taste with fleur de sel, Dijon and grainy mustard, horseradish, and pepper from the mill.
The bouillon can be made ahead and refrigerated for up to 3 days or frozen for up to 2 months, and the vegetables can be poached a few hours in advance. It's best to cook the beef right before serving, but leftovers can be covered and refrigerated for up to a couple of days and used for sandwiches or salads.
Excerpted from Around My French Table, © 2010 by Dorie Greenspan. Reproduced by permission of Houghton Mifflin Harcourt. All rights reserved.
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