Tarragon-Celery Soup

1 . Stage

Place a large pot over medium-low heat. Add butter and melt to coat the bottom of the pot. Add celery and onion; cook, stirring occasionally, until onion is translucent and celery is softened, 10 to 15 minutes. Keep the heat low enough so that the butter does not burn and onion does not brown or caramelize. Add garlic; cook and stir until aromatic, about 1 minute. Stir in salt, white pepper, tarragon, and cayenne.

2 . Stage

Meanwhile, place a medium pot over very low heat. Add milk and chicken broth and allow to warm slowly. Do not allow to boil or scald.

3 . Stage

Stir flour into the vegetable mixture until no dry flour remains. Pour in all but 1 cup of the warm liquid and bring to a low simmer.

4 . Stage

Whisk cornstarch into the remaining cup of liquid until there are no lumps. Add the cornstarch mixture to the vegetables. Stir in sherry. Bring to a simmer and cook over low heat until warm throughout and slightly thickened, about 10 minutes.

5 . Stage

Blend half of the soup in the bowl of a food processor or blender, then add back into the pot and serve.