Nibblous | potage veloute aux champignons (cream of mushroom soup)

Ingredients

• 1/4 cup (60 ml) finely chopped onion
• 4 tbsp (60 ml) butter
• 3 tblsp (45 ml) flour
• 6 cups (1.5l) fresh or canned chicken broth
• 2 sprigs parsley
• 1 bay leaf
• 1/4 tsp (1 ml) dried thyme
• salt and freshly ground pepper to taste
• the stems from 1 lb (500 g) mushrooms, chopped
• the caps from 1 lb (500 g) mushrooms, thinly sliced
• 2 egg yolks
• 1/2 cup (125 ml) whipping cream