2 medium onions [about 8 ounces total], ends cut flat, peeled, cut in half lengthwise
1 3/4 sticks unsalted butter [7 ounces], cut into 14 pieces
2 small carrots [about 4 ounces total], peeled, cut to fit the feed tube vertically
3 plum tomatoes [about 9 ounces total], quartered and seeded
3 1/2 pounds fresh spinach, washed, stems removed
1 cup veal stock, preferably homemade
1/2 cup Sauternes
Salt and freshly ground black pepper
6 slices calf's liver [about 5 ounces each], trimmed
Slice the onions thin, and saute in 2 tablespoons butter over low heat until the onions begin to exude their liquid, about 5 minutes. Cover and cook, stirring occasionally, until the onions are golden and very soft, about 25 minutes more.
For flower−like carrot slices, make 5 evenly−spaced lengthwise cuts on each carrot piece with a fruit and vegetable stripper; slice them into very thin rounds. Reserve.
Coursely chop the tomatoes. Reserve.
Bring a large pot of water to the boil, add the spinach and cook for 2 minutes. Drain and rinse under cold running water until cool enough to handle. Squeeze the spinach to remove all the liquid. Pulse the spinach, in a food processor until finely chopped, about 6 times. Add the onions and process until smooth, about 1 minute. Reserve.
To make the sauce, bring the stock, Sauternes and chopped tomatoes to the boil in a medium skillet. Cook until reduced by one−third, about 9 minutes. Strain into a small saucepan, pressing on the tomatoes to exude all their liquid: there should be about l/2 cup. Set the skillet aside. Whisk 8 tablespoons of the butter, one piece at a time, into the reduced liquid, over low heat. Season to taste and keep warm.
Add 2 tablespoons butter to the skillet used to reduce the sauce. Add the spinach mixture and season to taste. Keep warm, stirring occasionally.
Season the liver with salt and pepper. Cook 3 slices in 2 tablespoons
butter over medium high heat until golden brown on the outside but still
pink on the inside, about 2 minutes on each side. Remove to a plate and
cover loosely with foil to keep warm. Cook the remaining liver, adding
more butter as necessary.
Meanwhile, blanch the carrot slices in boiling water until just tender,
about 2 minutes. Drain.
Fill a pastry bag fitted with a l/2−inch star tip with the spinach
mixture. Pipe some spinach around the inner rim of 6 individual serving
plates. Cut each piece of liver diagonally into 3/4 inch wide slices and
arrange spoke−fashion on each plate. Spoon an equal amount of the sauce
on each serving and garnish with the carrot slices.