- 5 lbs onions, unpeeled
- 1⁄2 cup butter (1 stick)
- 1 1⁄2 teaspoons black pepper, freshly ground
- 2 tablespoons paprika
- 1 bay leaf
- 7 (16 ounce) cans beef broth, divided (recommended Swanson's)
- 1 cup dry white wine (optional)
- 3⁄4 cup all-purpose flour (such as Wondra) or 3/4 cup instant flour (such as Wondra)
- caramel coloring (optional) or Kitchen Bouquet (optional)
- 2 teaspoons salt
- French baguette (optional)
- swiss cheese (optional) or gruyere cheese (optional)
- Peel onions and slice 1/8 inch thick, preferably in a food processor.
- Melt butter in a 6-quart (or larger) stockpot. Add onions; cook, uncovered, over low heat for 1 1/2 hours, stirring occasionally.
- (The long cooking time makes the onions mellow and sweet.) Stir in pepper, paprika and bay leaf; saute over low heat 10 minutes more, stirring frequently.
- Pour in 6 cans broth and wine. Increase heat and bring to a boil.
- Dissolve flour in remaining 1 can broth.
- Stir into boiling soup.
- Reduce heat and simmer slowly for 2 hours.
- Adjust color to a rich brown with caramel coloring, season with salt. Refrigerate overnight. To serve, heat soup in microwave or on stove top.
- If desired, pour into ovenproof crocks or bowls.
- Top with a slice of bread and a sprinkling of grated cheese. Heat under the broiler until cheese melts and bubbles, about 5 minutes.
- Leftover soup can be frozen.