Prepare the mushrooms by removing the stems from the caps.

Cook the chopped onions in about 1 oz butter until soft but not browned, adding garlic just before onions are done.

Remove from heat and blend in the flour, mixing in well.

Mix in the boiling stock, and return to heat.

Mix in the mushroom stems and season to taste.

Simmer for about 30 minutes, partly cover the pan with the lid.

After 30 mins, strain the liquid from the stems, or place in a blender and bring to a pulp.

Return the soup to the saucepan.

In a separate pan, melt a little butter and cook the mushroom caps with the salt and lemon juice.

Put a lid on this saucepan and cook on low heat for about 5 minutes.

Now, transfer the mushroom caps and all their juices to the strained mushroom soup base.

Simmer for about 10 minutes.

When almost ready to serve, beat the egg yolks with the cream in a mixing bowl.

Add a little of the soup mixture to the egg and cream mixture, mixing it in well. Add more until you have about ½ pint.

Add the rest of the egg and cream mixture.

Return it all to the saucepan and cook very slowly for about 3 minutes.

Pour the soup into either a soup terrine or individual soup dishes.

Garnish with mushrooms or fresh herbs if you prefer.