From Michael Nagrant
8 pounds yellow onions
8 ounces unsalted butter
1 ½ teaspoons all purpose flour
2 cups Champagne (dry Brut style)
15 cups beef stock (Swanson is fine, homemade is better)
15 cups chicken stock (Swanson is fine, homemade is better) – you cut with chicken, because otherwise the soup is too rich.
7 medium stalks of fresh thyme
2 bay leaves
(put the thyme, bay, and peppercorns above in a cheesecloth and tie off to create a sachet)
1 lb lamb shoulder cut in cubes
1 tablespoon olive oil
Cut off tops and bottoms of the onions, then cut the onions lengthwise in half. Remove the peels and tough outer layers. Cut a V wedge in each one to remove the core.
Lay an onion half cut side down on a cutting board with the root end towards you. Note that there are lines on the outside of the onion. Cutting on the lines (with the grain) rather than against them will help the onions soften.
Melt the butter in a large heavy stockpot over a medium heat. Add the onions and 1 tablespoon salt, and reduce the heat to low. Cook stirring every 15 minutes and regulating the heat to keep the mixture bubbling gently, for about 1 hour, or until the onions have wilted and released a lot of liquid. Continue to stir the onions every 15 minutes being sure to scrape the bottom and corners of the pot, for about 3 hours or until the onions are caramelized (i.e. dark golden brown) throughout. Remove from the heat
In an 8 quart or larger pot, heat olive oil over medium until shimmering, add lamb and caramelize until brown. Transfer about two cups of the caramelized onions (you may have more from previous step, save for another application, pizza or sammies) to the pot. Sift in the flour and cook over a medium-high heat, stirring for 2 to 3 minutes. Add the beef stock, chicken stock, and champagne, bring to a simmer, and simmer for about 1 hour. Season to taste with salt, pepper and a generous squeeze of lemon. You can also finish with a touch more champagne or cognac to serve. Remove from heat.