Creamy Celery Soup
From Martha Stewart

2 Tablespoons butter
1 1/2 Pounds (12 to 15 large stalks) celery, sliced 1/2 inch thick crosswise (about 6 cups), leaves reserved for garnish
1 medium onion, coarsely chopped
1 baking potato, (8 to 10 ounces),peeled and cut in 1/2 inch cubes
Coarse salt
1 to 2 Tablespoons fresh lemon juice

1. Heat butter in a large (4-quart) saucepan over medium heat. Add celery, onion, and potato; season with salt. Cook, stirring occasionally, until vegetables begin to soften, 8 to 10 minutes.
2. Add 6 cups water to saucepan; bring to a boil.
3. Reduce heat to medium, and simmer until vegetables are very tender, about 20 minutes.
4. Working in batches, purée soup until smooth. (To prevent splattering, fill blender only halfway, and allow the heat to escape: Remove cap from hole in lid; cover lid with a dish towel, holding down firmly while blending.) Return soup to pan; stir in lemon juice, and season with salt.
5. Serve, garnished with celery leaves.

Serves 4.