Boil the potatoes in salted water for about 15 minutes.
Heat a frying pan without oil or butter and fry the bacon until crispy.
Add the onion in the last 2 minutes.
Heat the sausage according to the directions on the package.
In the last minute, add the endive to the boiling potatoes. Drain and drain well.
Return the mixture to the pan and add the mustard and butter.
Mash with the masher to a puree.
Stir the onion and bacon through the stew and season with pepper and the soy sauce.
Serve with the smoked sausage