Place the sweet potatoes and smoked garlic cloves in a large saucepan, cover with cold water and bring to the boil. Reduce the heat and simmer for 10–12 minutes until tender, then drain well.
Return the sweet potatoes and garlic to the pan and mash until smooth.
Set the pan over a low heat, then push the mash to one side, add the butter to the base of the pan and leave to melt. Pour the milk on to the butter and heat for 1–2 minutes, then beat into the mash.
Stir in the parsley, season to taste with salt and pepper and serve.