Onion Stew and Cheese Croutons

For the soup:

Melt the butter in a large saucepan and add the peeled and thinly sliced onions. Cover and cook over low heat for about 15 minutes, then remove the cover and cook until they are golden brown, stirring occasionally. Be careful not to over caramelize them as they will make the soup taste bitter.

Stir in 2 cups water, wine, broths, thyme, bay leaf, and 1/2 teaspoon salt, scraping up any final bits of browned crust on bottom and sides of pot. Increase heat to high and bring to simmer. Reduce heat to low, cover, and simmer 30 minutes. Remove and discard herbs, then season with salt and pepper.

In a small bowl, mix flour with about 1/4 cup water until thoroughly blended. Add this mixture to the soup and stir until it comes back up to the boil. Simmer for a few minutes until the soup has thickened, then remove from heat.

For the croutons:

While soup simmers, arrange baguette slices in single layer on baking sheet and bake in 400-degree oven until bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.

Adjust oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on baking sheet and fill each with about 1 3/4 cups soup. Top each bowl with 1 or 2 baguette slices (do not overlap slices) and sprinkle evenly with Gruyère. Broil until cheese is melted and bubbly around edges, 3 to 5 minutes. Let cool 5 minutes before serving.