1crusty, artisan bread loaf, cut into 1’’ cubes (or bite size pieces), preferably very stale (about 6 cups total)
5Tbspolive oil or melted butter
6cshredded Gruyere cheese, substitute or add Swiss, coastal cheddar, gouda, and/ or Parmesan
Instructions
Make the croutons:
If you’re using fresh bread, cut the loaf into cubes and arrange in a single layer on a rimmed baking sheet. Add to an oven set to 250 degrees and bake until dried out and hardened, 15-20 minutes.
To toast the bread cubes, set the broiler to high, toss the cubes in the olive oil or butter, and sprinkle with salt. Place the baking sheet back into the oven 2 racks below the broiler, and toast for 4-6 minutes (depending on the broiler) tossing 2-3 times in between until all sides are golden.
Remove from the oven and let sit until ready to use.
Make the soup:
In a large pot or Dutch oven, melt the butter over medium-high heat. Add the onions and season with sugar and salt. Toss in the butter, then top with a lid and let sit for 12-15 minutes, stirring 1-2 times.
Once the onions have sweated and are softened, remove the lid. Stir semi-frequently, as the onions reduce for 35-45 minutes. If you notice the onions are starting to burn, lower the heat as needed and add splashes of water to prevent burning.
Note: As the onions get closer to being done, golden, sticky fond will start to form on the bottom of the pan. Simply scrape it up with a spatula, or add water, one teaspoon at a time, to prevent it from burning.
After 35-45 minutes, lower the heat to medium low. By this point the onions should be significantly reduced, golden and jammy. Add in the red wine and scrape up any fond from the bottom of the pan. Reduce the wine for 5 minutes, then add the beef stock, fish sauce, black pepper, bay leaves, and thyme.
Bring to a boil, then reduce the heat and simmer for 30-45 minutes.
Portion out the soup into ramekins arranged on a parchment-lined baking sheet. Top each portion with about 1/2 cup of cheese followed by a layer of croutons, and another 1/2 cup of cheese. Place in the oven, 3 racks below the broiler, set to high. Broil until melted and golden—5-8 minutes depending on the broiler.
Let soup chill a few minutes before garnishing with fresh chives and serving warm.
Notes
Croutons: Often, French onion soup is made with crostini like croutons (stale, toasted bread slices), but I prefer to use bread cubes, because they are friendlier to eat with a spoon, given that they require not cutting or breaking like sliced bread.
You can bake fresh bread cubes in the oven as instructed below, or, you can let them sit out uncovered on a baking sheet for 1-4 days until very dry and stale.
I prefer having very dry cubes, because, after toasting with butter and salt, they absorb the broth like sponges and still manage to have a bit of crunch in the center, which I love because it adds textural contrast to the jammy soup.