Celeriac is a root vegetable which provides a wonderful celery flavour with a slight nuttiness.
6 potatoes, peeled and diced
1 celeriac bulb, peeled and diced (do not peel in advance, as celeriac tends to discolour)
1 tbsp salt
2 cloves garlic, peeled
1 cup milk (quantity may vary depending on absorbency of the potatoes and desired consistency).
Place potatoes, celeriac, garlic and salt in a large pot and cover with water. Boil for 15-20 minutes or until vegetables are soft. Drain well and mash with butter and milk until smooth. Season to taste.