Peel the swede, quarter, and cut into 2"/5cm chunks.
Place the swede in a saucepan, cover with salted water, and bring to the boil. Cook for 15–18 minutes, until soft.
Once cooked, strain the swede in a sieve or colander. Allow to drain for a few minutes so that the swede is dry. This stops the mash becoming watery.
Put the swede back into the saucepan. Add butter and milk or cream. Chop the swede up with a sharp knife (this makes mashing much easier).
Mash the swede. For the smoothest results, use a stick blender or food processor.
Check seasoning, and add pepper and extra salt to taste. Top with a knob of butter and serve.
