Melt the butter in a deep, heavy-bottomed soup pot over medium heat.

Add the sliced onions, peeled and chopped parsnips, peeled and chopped carrot, thyme branch, and bay leaf.

Season generously with salt and pepper.

Cook, stirring frequently, until the onion is soft and lightly browned, about 10 minutes.

Add the chicken or vegetable broth and the soaked, drained dried mushrooms.

Bring to a boil, then adjust the heat to a gentle simmer.

Meanwhile, heat the olive oil over high heat in a wide skillet.

When the oil is hot, add the sliced chanterelles or other wild or cultivated mushrooms, stirring, allowing them to brown a bit.

Season with salt and pepper, then turn the heat to medium and sauté for 5 to 7 minutes, until the mushrooms are cooked through.

Add the minced garlic and thyme leaves and cook 1 minute more.

Transfer 1/2 cup of the cooked chanterelles to a small skillet and add the rest to the soup.

Let the pot simmer until the parsnips and carrot are quite tender, about 15 to 20 minutes.

Discard the bay leaf and thyme branch.

Puree the soup in a blender until smooth.

Strain the soup through a fine-meshed sieve for a silky texture.

Thin with more broth if it is too thick, and correct the seasoning to taste.

Keep the soup hot until serving.

Warm the reserved mushrooms in the small skillet.

Toast the baguette slices lightly until golden brown.

Top each toast with a spoonful of warmed mushrooms.

Ladle the hot soup into bowls.

Top each bowl with a mushroom toast, a little chopped parsley, and a drizzle of creme fraiche (optional).