Preparation: The Onions: Drop the onions into boiling water for 1 minute. Drain. Shave skin from the tip and root ends, then slip off the remaining skins. Pierce a cross 1/4 inch deep in the root ends, for even cooking. Simmer slowly in the covered saucepan with the stock, herbs , and a little salt until tender, about 20 minutes. Meanwhile, continue with the rest of the items. The Potatoes: Peel the potatoes and cut into 3/4-inch slices; cut the slices into 3/4-inch strips, and cut the strips into cubes. Dry the potatoes. Set one of the frying pans over high heat, add 1 tablespoon each of butter and oil, and when the butter foam has almost subsided, add the potatoes. Saute without disturbing for 1 minute, swirl the pan by its handle to toss them, and leave for another minute to sear them. Season lightly with salt and pepper , and saute over moderate heat, tossing fairly frequently, for about 15 minutes. When lightly browned and tender, keep them just warm, uncovered, over a pan of barely simmering water. The Mushrooms : Trim 1/4 inch off the stems of the mushrooms and either wipe the caps clean with a towel or wash them rapidly, if dirty, and dry them. Quarter them. Saute several minutes in hot butter in your second frying pan, adding the shallots or scallions at the end, just as the absorbed butter reappears on their surface and they begin to brown. The Meat: Whether you are using steaks or a piece of tenderloin, cut off outside fat and slice the meat into 1-1/2-inch chunks. Dry them well before sauteing. Midway point: Everything is cooking at once except for the meat , which is lying in wait. The onions are simmering away in their saucepan; the potatoes are sauteing. When the mushrooms are done, turn them into a side dish. Sauteing the meat : Set the mushroom saute pan over moderately high heat, adding a little butter and oil. When very hot, almost smoking, add the meat . Brown, tossing frequently for several minutes, until barely springy when pressed -- the beef must be very rare because it gets a little more cooking later. Toss it with a sprinkling of salt , and scrape it into the dish with the mushrooms . The Sauce: Spoon all but a tablespoon of fat out of the pan, stir in the minced shallots or scallions, and saute a moment; then pour in the wine , the stock, and any juices from the onions. Boil rapidly and let reduce almost to a syrup before adding the optional cream (or the stock/cornstarch). Final simmering: Scrape the beef , onions, and mushrooms into the pan and bring to the simmer, basting with the sauce, just to warm the beef through without overcooking; it should be rosy rare. Taste the sauce carefully and correct seasoning. Serving: Toss the potatoes over high heat to crisp, adding a tablespoon of butter, the herbs , and parsley. Strew the potatoes over the meat and serve. Yield: 2 servings Source: The Way to Cook by Julia Child (Alfred A. Knopf) Reprinted with permission.