Celery Root Purée with Toasted Hazelnuts

Ingredients

• 10 servings pepper black freshly ground
• 3 pounds celery root peeled cut into 1/2" cubes
• 1 tablespoon hazelnut oil 
• 0.3 cup hazelnuts toasted coarsely chopped
• 0.7 cup heavy cream 
• 10 servings kosher salt 
• 3 pounds russet potatoes peeled cut into 1" cubes
• 0.5 cup butter unsalted chilled cut into 1/2" cubes (1 stick)
• 0.7 cup milk whole

Equipment

• bowl
• sauce pan
• pot
• potato ricer

Directions

1. Place celery root and potatoes in a largeheavy pot.
2. Add cold water to cover; seasonwith salt. Bring to a boil over medium-highheat. Reduce heat; simmer until vegetablescan be pierced with a fork, 20-25 minutes.
3. Drain vegetables well. Pass vegetablesthrough food mill or potato ricer intosame pot.
4. Meanwhile, bring cream and milk just toa simmer in a medium saucepan; removefrom heat. Stir vegetable purée constantlyover medium-low heat until excess moistureevaporates, about 2 minutes.
5. Stir butter into purée a few pieces at atime, blending between additions.
6. Removefrom heat; slowly fold in cream mixture untila smooth purée forms. Season to taste withsalt and pepper. DO AHEAD: Purée can bemade 1 day ahead. Cover; chill. Rewarm in amicrowave or in a heatproof bowl set over alarge pot of simmering water.
7. Strain hot purée through a medium-meshsieve into a serving bowl (this makes thetexture especially smooth and creamy).
8. Drizzle with oil; scatter hazelnuts over.