Slow roasted onion & golden apple soup recipe

Ingredients

• 4 lb [4.8 kg] large yellow onions (about 6 large onions)
• 4 Tbsp [55 g] unsalted butter
• 2 tsp salt
• 2 small Golden Delicious apples, peeled, cored, and chopped
• 7 fresh thyme sprigs
• 2 dried bay leaves
• 1 fresh rosemary sprig
• ¾ cup [180 ml] apple cider
• ½ cup [120 ml] bourbon (or apple cider, apple brandy, or sherry)
• 4 cups [960 ml] beef stock
• 2 cups [480 ml] chicken stock
• Freshly ground pepper
• 1 baguette, sliced ¼ to ½ in [6 to 12 mm] thick
• 2½ cups [200 g] shredded Gruyère cheese (or a good Swiss cheese)
• 1½ cups [180 g] crumbled blue cheese

1. Preheat the oven to 400°F [200°C]. Thoroughly coat the inside of a Dutch oven or large, heavy-bottomed, ovenproof pot (at least 7 qt [6.6 L]) with nonstick cooking spray.
2. Peel and halve the onions, and cut them into ¼-in- [6-mm-] thick slices. Combine the butter, onions, and 1½ tsp of the salt in the pot (no need to cut up the butter; it will melt into the onions as they cook). Cover the pot, place it in the oven, and cook for 1 hour. Remove the pot from the oven and give the onions a stir. With the lid slightly askew this time, return the pot to the oven and cook for 1 more hour. Add the apples and stir. Cover the pot completely, and return it to the oven for 30 more minutes. Meanwhile, using kitchen string, tie the thyme, bay leaves, and rosemary sprigs into a tight bundle and set aside.
3. Remove the pot from the oven and lower the oven temperature to 350°F [180°C] for the croutons.
4. Place the pot over medium heat, add ¼ cup [60 ml] of the apple cider, and stir to scrape up all of the browned bits on the bottom. Cook, without stirring, until the cider has evaporated and a crust has formed on the bottom of the pot, 5 or 6 minutes. Repeat this deglazing and reducing process two more times, adding another ¼ cup [60 ml] of the cider each time. The onions should be a very dark brown. Add the bourbon and cook, stirring frequently and scraping up the crust on the bottom of the pot, 5 minutes. Add both stocks, 2 cups [480 ml] of water, the herb bundle, and the remaining ½ tsp of salt. Bring to a simmer, and turn the heat to low. Cover the pot, leaving the lid slightly askew, and let the soup simmer gently for 20 minutes. Remove the herb bundle and season the soup with salt and pepper.
5. Place the bread slices on a baking sheet in one layer and bake until they are dry, crispy, and golden brown, 4 to 5 minutes.
6. When you’re ready to serve the soup, place an oven rack about 6 in [15 cm] from the broiler. Place six individual broiler-safe crocks, bowls, or large ramekins on a baking sheet and ladle in enough soup so they are three-quarters full. Top each serving with a couple of bread rounds and pile them high with Gruyère and then blue cheese. Broil until the cheese is melted and bubbling around the edges, 2 to 4 minutes. Serve immediately.