Celery Root Purée with Sage and Black Pepper

For celery root purée with a clean, pure flavour, we processed chunks of the peeled root, along with russet potato for body, in the food processor to create tiny pieces that would cook quickly in small amounts of water and butter. To help the vegetables cook even more quickly, we added a small amount of baking soda to the cooking liquid. This created an alkaline cooking environment that sped up their breakdown. Once the vegetables and water had cooked into a thick mush, we returned it to the processor and buzzed it with some heavy cream to form a smooth purée. For a flavourful topping, we cooked shallot and fresh sage in butter until the shallot was golden and the sage was crisp and then finished the topping with a touch of black pepper.

Celery Root:
1¾-2 lbs celery root, peeled and cut into 2" chunks
1 (6 oz) russet potato, peeled and cut into 2" chunks
2 Tbsp. unsalted butter
1 cup water
½ tsp. kosher salt
¼ tsp. baking soda
⅓ cup heavy cream

Topping:
2 Tbsp. unsalted butter
1 small shallot, minced
1 Tbsp. fresh sage, minced
¼ tsp. black pepper, freshly ground
pinch kosher salt

When buying celery root, look for one with few roots for easy peeling and minimal waste. Use a chef's knife to peel the celery root: Trim the top and bottom of the root first, and then cut the skin away from the sides. Once it's prepped, you should have about 1½ lbs of celery root. While the celery root purée can be made in advance, the topping should be made as close to serving as possible. For the best results, do not substitute dried sage.

For the Celery Root:
Working in 2 batches, pulse celery root and potato in food processor until finely chopped, about 20 pulses per batch; transfer to bowl. (You should have about 4½ cups chopped vegetables.)

Melt butter in large saucepan over medium heat. Stir in celery root-potato mixture, water, salt, and baking soda. Cover and cook, stirring often (mixture will stick but cleans up easily), until vegetables are very soft and translucent and mixture resembles applesauce, 15-18 minutes. While celery root cooks, make topping.

For the Topping:
Melt butter in 8" nonstick skillet over medium-high heat. Add shallot and sage and cook, stirring frequently, until shallot is golden and sage is crisp, about 3 minutes. Off heat, stir in pepper and salt. Cover to keep warm.

Uncover celery root mixture and cook, stirring vigorously to further break down vegetables and thicken remaining cooking liquid, about 1 minute. Transfer celery root mixture to clean, dry food processor. Add cream and process until smooth, about 40 seconds. Season with salt to taste. Transfer to bowl, drizzle with topping, and serve. (Ungarnished purée can be cooled and refrigerated for up to 2 days. Before serving, microwave purée on medium-high power in covered bowl, stirring often, until hot throughout, 7-10 minutes.)

Makes 4-6 servings.