Because you will need to cook the gnocchi quickly once the batter is ready, do the following before you begin the preparation. Bring a large stockpot of salted water to a boil and reduce to a simmer. Have a large bowl of iced water nearby.
Combine milk, butter, and 1/2 teaspoon salt in a medium-heavy saucepan. Bring to a boil over high heat. Add flour and stir vigorously with a wooden spoon until mixture is nearly solid, about 2 minutes. The batter should be the consistency of mashed potatoes and should clear the sides of the pan to form a ball. Remove from heat.
Transfer to a large bowl and add eggs, one at a time, beating well after each addition. (An electric mixer is fine for this.) The batter should be very thick, shiny, and smooth. Fill a pastry bag, fitted with a large plain tip #8, with batter.
Holding pastry bag over simmering water, gently squeeze out dough, slicing into 1-inch lengths with a paring knife.
Working in 4 batches of about 20 pieces, cook gnocchi at a slow simmer, stirring occasionally, until they start to puff, about 5 minutes. They should resemble floating corks. To test for doneness, remove a dumpling and cut in half. The center should have tiny bubbles. With a slotted spoon, transfer gnocchi to the bowl if iced water to cool. Drain well in a colander. At this stage, you can store gnocchi in refrigerator up to 2 days.
Preheat oven to 450 degrees F.
Bring Tomato Coulis and cream to a boil in a large ovenproof skillet or casserole. Add Parmesan, salt, pepper, and gnocchi. Return to a boil, sprinkle with cheese and transfer to oven. Bake until sauce is thick and bubbly and a slight crust forms on top, about 7 minutes. Garnish with chopped chives and serve immediately.
Melt 2 tablespoons butter in a medium skillet over low heat. Cook onion, mushrooms, shallot, leek, and salt until soft, about 7 minutes. Add brandy and 1/4 cup Madeira. Turn heat to high and light alcohol with a match. Cook over high heat until liquid is reduced by half.
Add chicken stock, tomatoes, thyme, and bay leaf. Reduce the heat to low and simmer, uncovered, for 20 minutes. Puree in a food processor or blender and strain.
Return to pan and place over medium heat. Whisk in remaining tablespoon butter, broken in small pieces, and remaining tablespoon Madeira. Season with salt and pepper to taste and serve.
c.1998, M.S. Milliken & S. Feniger, all rights reserved