french onion mushroom soup
Low and slow and well worth it, ho.
Ingredients
- 4 tbsp butter
- 4 large yellow onions, thinly sliced
- 2 cups mixed mushrooms (I used beech), sliced if large
- 1/4 cup all purpose flour
- 1/4 cup sherry vinegar
- 1 tbsp Worcestershire sauce
- 3 bay leaves
- 6-8 cups beef broth, vegetarian or regular
- 1 loaf sourdough or baguette, sliced
- 1 clove garlic, peeled
- 2 cups Gruyere cheese, shredded
- fresh thyme/oregano, for serving
Instructions
- Melt the butter in a large soup pot or Dutch oven over medium heat. Toss in the onions and mushrooms and season generously with salt and pepper (about 1/2 tsp each to start).
- Cook the onions and mushrooms, stirring every 5 to 10 minutes, for 45-60 minutes. Monitor the heat very closely. If the goodies start to brown too quickly, reduce the heat to medium-low. The onions will take a long time to caramelize!
- Once the onions are deeply golden and jammy in texture, stir in the flour. Pour in the sherry vinegar and Worcestershire, stir, then add the broth. Bring to a simmer and toss in the bay leaves. Cook for 10-15 minutes until the soup thickens slightly. Taste and adjust salt and pepper as needed.
- Towards the end of the soup's cooking time, heat your broiler. Place the slices of bread on a baking sheet. Brush with a small amount of butter (about 1 tablespoon divided between all the slices) and rub with the garlic clove. Sprinkle with cheese. Broil for 2-3 minutes until bubbly, melty, and golden around the edges.
- Divide the soup into bowls or crocks and top with 1-2 cheese bread slices. Garnish with fresh thyme or oregano and a pinch of freshly cracked pepper.
Notes
*Mushrooms: I liked beech mushrooms for the stringy texture akin to the sliced onions. You can use shiitake, sliced baby bella, or even shredded king oyster mushrooms.
*Gruyere substitute: If you can't find gruyere or it is too costly for you, Swiss is your best alternative.