Champignon Bisque

Why I Love This Recipe
I don't even remember where I originally got this recipe, I think it is Martha Stewart from 13 years ago.... In any case, regardless of origin, it is delicious.
Ingredients You'll Need
4 TB Unsalted Butter
6 TB AP Flour
1/2 cup finely minced leek (White parts only)
3 quarts Vegetable stock
2 TB Fresh Italian Parsley Chopped Fine
1 TB Thyme leaves
1 Bay leaf
4 TB Unsalted Butter
2 lbs White button mushrooms (sliced)
Juice of 1/2 Lemon
zest of 1/2 Lemon
1 cup Heavy Cream
4 Egg yolks
Salt to Taste
White pepper to taste
Directions
In a Stock pot, sweat Leeks in 4 TB butter until tender; Remove and add flour;
Cook Roux until golden brown.
Add vegetable stock and stir until roux dissolves.
Add Parsley, Thyme and bay leaf.
Bring to a simmer.
In a separate skillet, over medium high heat, melt another 4 TB butter and Saute Mushrooms with Salt and white pepper to taste.
Add Lemon Juice and zest; Continue cooking
Meanwhile, Whisk Egg yolks with heavy cream in a medium bowl.
Remove mushrooms from saute pan and add to the stock pot.
Continue reducing the left over liquid from the mushroom saute.
Condition yolks and cream, then add to the stock pot, along with the essence left in the skillet from the reduction.
Simmer soup for about 20 minutes more (Do not boil)
Serve with sourdough bread and slices of Brie or Havarti