Bring a large pot of water to a boil and add a generous pinch of salt. Blanch the asparagus until crisp yet tender, 2 to 3 minutes, depending on the thickness. Shock the asparagus in a bowl of ice water. When cool, drain well and chop the asparagus spears into 1-inch pieces. Set aside.

Melt the butter in a large, heavy pot over medium heat. Gently sauté the leeks and celery until softened, 4 to 5 minutes. Add the garlic and cook an additional minute.

Sprinkle in the flour and cook, stirring, for 2 additional minutes.

Gradually whisk in the stock, and bring to a boil. Tie the parsley, thyme and bay leaf into a bundle with a piece of kitchen twine and add to the soup. Lower the heat, and simmer for 10 minutes. Remove and discard the herb bundle.

Stir the blanched asparagus into the soup base.

Working in batches, transfer the soup to a blender, and puree until smooth.

Return the pureed soup to the pot and reheat over medium heat. Whisk in the heavy cream and add the lemon juice to taste. Season with salt and pepper.

Divide the bisque among warm soup bowls, top with a dollop of crème fraîche and finish with a sprinkling of hazelnuts.