1. Peel the topinambour and potatoes and cut into equal pieces. Peel the garlic. Boil the topinambour, potatoes together with the garlic and a bit of salt in a large cooking pan for about 25 min. drain and leave to evaporate for 5 minutes leaving the lid on the pan.
2. Finely cut the parsley. Add the milk and butter and mash until it is a rough puree. Mix the parsley through the puree and bring to taste with salt and pepper.