Peel the potatoes and clean the peppers. Wash both and roughly dice. Peel and finely dice the onions.
Melt the butter in a saucepan. Sweat the onions in it until translucent. Add flour and chili powder and sauté for 2 minutes while stirring. Pour in the broth while stirring and bring to the boil. Season with salt and pepper. Put the potatoes and peppers in the boiling sauce and cook over a mild heat for about 25 minutes. Add the sprigs of thyme.
Cut the sausage into slices. Heat the oil in a pan and fry the sausage all over over a medium heat. Remove the sprigs of thyme from the ragout. Stir in the creme fraiche and season again with salt and pepper. Heat the sausage in it.