Step 1

Caramelize Onions: In a large heavy pot such as a Dutch oven, add the olive oil and 2 tbsp of butter. Cook on medium until butter melts. Add the onions and give them a stir to coat them in the oil. Cover the pot with a lid and cook for 20 minutes with the heat still on medium, stirring every few minutes. After 20 minutes the onions should be transparent.

Step 2

Remove the lid and stir in the sugar and salt. Continue cooking for another 40 minutes, stirring occasionally. The onions are done when they are a deep golden color and sweet.

Step 3

Make a Roux: Add the flour, and remaining 1 tbsp of butter and stir. Cook for about 2 or 3 minutes, just enough to cook the flour and remove that flour taste.

Step 4

Deglaze: Add 1 cup of the beef broth to the pot and stir. Cook for about 1 minute while stirring to scrape the bottom of the pot. You'll see it evaporate almost immediately.

Step 5

Add broth, wine and herbs: Add the rest of the broth to the pot, followed by the red wine, bay leaves and thyme sprigs.

Step 6

Simmer: Bring to a boil, then turn down the heat and simmer for 30 minutes, uncovered.

Step 7

Season and add cognac: Taste for seasoning and adjust with salt and pepper if needed. Stir in the cognac.

Step 8

Add bread and cheese: Top the soup with about 1 cup of gruyere cheese. Add the slices of bread over the cheese. I prefer to toast my bread first then add it to the soup. To toast the bread, lightly sprinkle the bread slices with some olive oil, transfer them to a baking sheet and toast them under broil for about 30 seconds to a minute per side. Top the soup with toasted bread, then top with remaining gruyere and parmesan cheese.

Step 9

Melt cheese: Preheat your oven to 350 F degrees. Transfer the pot to the oven and bake until the cheese melts and starts to brown, about 20 to 25 minutes. Ladle into bowls and serve.