Quarter the peeled potatoes and the celeriac. Boil till they are tender and can be easily pierced with fork, around 15 to 20 minutes. While potatoes are boiling, fry (vegetarian) bacon and drain on kitchen paper. Mash the potatoes and celeriac with a potato masher (easiest) or fork, add a knob of butter, a splash of milk, a pinch of ground nutmeg and salt and pepper to taste. When it has a good taste and a creamy texture add in the (vegetarian) bacon and the endive. Serve immediately with a typical smoked (vegetarian) sausage.