Ingredients (servings: 6, cook time: 4hours)
- 3 tbsp olive oil
- 4 large onions, halved and cut into ¼-inch thick slices
- Table salt
- 1.5 cups (500 ml) water, plus extra for deglazing
- ½ cup (120 ml) dry red wine
- 4 cups (940 ml) korean bibigo beef bone broth
- 6 tbsp dried oregano
- 1 bay leaf
- Ground black pepper
- 1.5 cups shredded gruyere cheese
- Braise/Caramelize Onions: Adjust oven rack to lower-middle position and heat oven to 400 degrees F.
- Put olive oil in a oven safe large square casserole dish and add onions and 1 teaspoon salt. Cook, covered, 1 hour (onions will be moist and slightly reduced in volume).
- Remove pot from oven and stir onions, scraping bottom and sides of pot. Return pot to oven with lid/aluminum foil slightly ajar and continue to cook until onions are very soft and golden brown, 1½ hours longer, stirring onions and scraping bottom and sides of pot after 1 hour.
- Carefully remove casserole djsh from oven and transfer to a large pot. Place over medium-high heat, stirring frequently and scraping bottom and sides of pot, until liquid evaporates and onions brown, 15 to 20 minutes, reducing heat to medium if onions are browning too quickly. Continue to cook, stirring frequently, until pot bottom is coated with dark crust, 6 to 8 minutes, adjusting heat if necessary. (Scrape any crust that collected on spoon back into onions.) When the onions have turned golden brown, stir in red wine and cook, stirring frequently, until sherry evaporates, about 5 minutes.
- Finish the Soup: Stir in broths, 1.5 cups water, dried oregano, bay leaf, 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.
- When serving, sprinkle the shredded gruyere cheese on top and use a blow torch to melt the cheese and form a golden brown crust on top. (If you do not have a blow torch, you can put it under the oven broiler for about 3-5 minutes)