CELERY ROOT AND POTATO PURéE

Steps:

• Peel and cut into large pieces: 1 pound potatoes, preferably a yellow-fleshed variety such as Yellow Finn or Yukon Gold.
• Cook until soft in salted boiling water.
• Drain. Pass the potatoes through a ricer or food mill and return to the pot. For a chunkier consistency smash with a potato masher right in the pot. Stir in: 2 tablespoons butter.
• Peel, cut in half, and slice fairly thin: 1 medium celery root (about 3/4 pound).
• Melt in a heavy-bottomed pan over medium-low heat: 3 tablespoons butter.
• Add the celery root with: Salt.
• Cover tightly and cook until quite soft, 12 to 15 minutes, stirring now and then. Lower the heat if the celery root starts to brown. Pass through a food mill, or, for a smoother version, purée in a blender. Stir into the potatoes. If the purée is too thick, thin with: Milk.
• Taste and add salt or more butter if needed.