Chestnut and Sweet Onion Soup with Trompette Mushrooms from Today's special: A new take on bistro fo

Ingredients

• Salt and freshly ground black pepper
• 1 teaspoon chopped tarragon
• 1.5 litres chicken or vegetable stock or water
• 200 g fresh or frozen chestnuts, thinly sliced
• 1 teaspoon chopped rosemary
• 100 g trompettes des morts mushrooms, well cleaned and picked over
• 1 teaspoon chopped thyme
• 200 ml Madeira
• 75 g butter
• 100 g chestnut mushrooms, thinly sliced
• 2 white onions, finely chopped
• 1 tablespoon chopped parsley
• 4 garlic cloves, thinly sliced