View the original recipe via:
Peel, wash and roughly chop the potatoes. Peel, wash and roughly chop the celery root. It's best to cut it slightly smaller than the potatoes.
Place the potato and celery root pieces in a large pan and fill it with water and a good pinch of salt. Bring to a boil and turn down the heat once the water is boiling.
The exact cooking time depends on the size of the potato and celery root pieces.
Drain and mash the potato and celery root. You can use a potato masher for this or rub them through a fine sieve with a large ladle.
Add butter, milk and heavy cream and stir until you've reached a smooth puree. Season with salt, pepper and a pinch of nutmeg. Enjoy!