Braised Celery Root Purée With Mushrooms

Preparation

1. Step 1

   Preheat the oven to 375 degrees. In a small pot, bring 3 cups water to a boil. Remove from the heat, add the porcini and let sit for 30 minutes. Strain through a fine-mesh sieve set over a bowl and set aside. Rinse and chop the mushrooms.

2. Step 2

   Fill a large bowl with cold water and add all but 2 tablespoons of the lemon juice. Peel, quarter and cut the celery root into ¼-inch-thick slices and add to the water.

3. Step 3

   Place a large, ovenproof pot over medium-high heat. Heat ¼ cup of the oil, then add the leek, onion, garlic, thyme sprigs, bay leaf and a pinch each of salt and pepper. Sauté until the onions are translucent.

4. Step 4

   Drain the celery root and add it to the onion mixture with the reserved mushroom broth and milk. Bring to a boil, cover tightly and transfer to the oven. Braise until the celery root is tender, about 40 minutes.

5. Step 5

   Remove the bay leaf and thyme sprigs. Using a blender or immersion blender, carefully blend the mixture to a smooth purée. (For a finer texture, strain through a fine-mesh sieve.) Place the pot over low heat and simmer until it reaches the consistency of porridge. Add the remaining 2 tablespoons lemon juice and season to taste with salt and pepper.

6. Step 6

   In a large skillet over medium-high heat, heat the remaining ¼ cup oil. Add the fresh mushrooms and sauté until the water releases and evaporates. Add the rehydrated porcini and chopped thyme. Season with salt and pepper to taste.

7. Step 7

   To serve, place a few spoonfuls of the purée on each plate and drizzle with truffle oil, if using. Top with mushrooms and Parmesan.