Celery Root & Cauliflower Puree

Dice the vegetables. Rinse the celery and the cauliflower under cold water and pat them dry. Next, cut the celery root into 4 pieces to quarter it. Peel it and cut it into 1.5-inch (3.5 cm) cubes. Cut the cauliflower into florets.
Boil. Place the diced celery, cauliflower, halved shallots, garlic, and salt in a large pot and cover with water. The vegetables should be submerged. Bring to a boil, then lower the heat to a simmer and cook for 20-25 minutes or until the celery and cauliflower are tender. You can test doneness by pricking the celery with a knife or fork. It should be tender.
Drain. Once the vegetables are cooked, remove from the heat and drain them, discarding the cooking water.
Process. Transfer the cooked celery, cauliflower, shallots, and garlic to a food processor. Add the butter, nutritional yeast, ground black pepper, and a pinch of nutmeg. Process for 3-5 minutes or until you get a smooth purée. Taste and adjust the salt and pepper if needed (I ended up adding an extra 1/2 tsp salt).
Serve. Serve immediately or reheat gently in a saucepan with a few tablespoons of plant-based milk or cream to prevent the purée from drying. You can also reheat it over a double boiler.
You can store this purée in the refrigerator for up to 4 days.