Cheese loaf with caramelized onions

Ingredients:

• 0.5 cups lightly salted beef broth
• A pinch of ground nutmeg
• 1 teaspoon horseradish (do not drain the liquid)
• 4.5 tbsp unsalted butter
• 2 large onions, thinly sliced
• 1 teaspoon chopped fresh thyme
• 1 round loaf of sourdough bread, 20 cm in diameter.
• 450 g Gruyere, thinly sliced
• Chopped fresh parsley, for serving

Preparation:

1. Preheat oven to 350°F (175°C). Combine broth and nutmeg in a small saucepan and bring to a boil. Remove from heat and stir in horseradish and 1/2 tbsp butter.
2. In a large skillet over medium heat, melt the remaining 4 tablespoons butter. Add the onion, thyme, and 3/4 teaspoon salt and cook, stirring frequently, until the onion is golden and soft, about 20 minutes. Let cool slightly, then stir into the broth.
3. Using a large serrated knife, score the bread at 4 cm intervals, approximately three-quarters of the way down the loaf. Make similarly perpendicular cuts to create cubes on the surface of the loaf.
4. Place the bread on a parchment-lined rimmed baking sheet. Fill the slits with the Gruyère and onion mixture, breaking the cheese into smaller pieces as needed. Pour the remaining onion mixture into the slits. Cover the bread with foil and bake until heated through, about 15 minutes. Remove the foil and continue baking until the cheese is melted and the bread is golden brown, another 20-25 minutes. Sprinkle with parsley.