3 pounds yellow onions
3 tablespoons unsalted butter
1/2 teaspoon salt, plus more as needed
1 pinch sugar
8 cups water, plus more as needed
1 tablespoon all-purpose flour
1 sprig fresh thyme
1/4 cup dry white wine
1 baguette
8 oz Gruyere cheese (or Swiss cheese)
Cut the tips off the onions and slice them in half lengthwise pole to pole. Peel off the outer layer and the skin and cut each half in half lengthwise. Slice each quarter crosswise into 1/8 inch slices. As you get close to the roof, flip each piece onto the other flat side and continue slicing. Melt butter in a large Dutch oven or soup pot over medium heat. Once it has stopped foaming, add onions, 1/2 teaspoon salt, and sugar. Toss to evenly coat. Cover and cook 10 minutes. Remove cover, and cook stirring frequently until the onions begin to brown lightly (this took about 30 to 45 minutes). Now stir every 5 minutes and add a couple tablespoons of water whenever the bottom of the pan crusts over. Continue to cook as directed until the onions are an even dark walnut color, an additional 30 to 45 minutes longer.
Add the flour and stir for two minutes. Add eight cups of water and thyme sprig to the onions and bring to a boil. Lower heat to maintain a lively simmer and cook for 20 minutes. Add white wine and simmer 10 minutes longer. Taste for seasoning adding salt as needed. Meanwhile, heat the oven to 325 degrees and adjust a rack to the upper middle position. Cut the baguette into 3/4 inch slices and arrange on a single layer on a cookie sheet. Bake until the bread is dry, crisp and very lightly colored at the edges, about 10 minutes. Remove bread slices and set aside.
Heat broiler and place 5 or 6 heatproof bowls in a baking sheet. Feel each bowl with 2 cups soup. Top each with two baguette slices and evenly distribute grated cheese over the bread. Broil until well browned and bubbly, about 10 minutes. Cool for five minutes before serving.
Printed from The Sweet and Savory Kitchen