In a large saucepan on a high heat, simmer the potatoes for 5 mins in enough water to just cover them, then drain in a colander and leave for 1 min for the steam to escape.
Heat the oil in a large frying pan on a high heat, add the bacon and cook for 8-10 mins until lightly caramelised. Add the potatoes, then the lactose free butter.
Season with salt and freshly ground black pepper and cook for 10 mins, stirring regularly, until golden brown all over.
Spoon out any excess fat and stir in the herbs. Taste and adjust the seasoning if necessary. Top with the grated parsley.