Season the potatoes with salt. Heat a little clarified butter in a non-stick frying pan. Add the potatoes, fry for approx. 5 mins., stirring occasionally. Shape the roesti into a patty. Continue to fry the roesti over a medium heat for a further 15 mins. until a golden crust forms. Place a large, flat plate on top of the pan. Tip the roesti out onto the plate. Add a little clarified butter to the pan, slide the roesti back into the pan with the uncooked side facing down, finish cooking for approx. 10 mins. Place the cheese on the roesti, cover the pan with a lid and allow the cheese to melt.
Combine the pears, water and sugar in a pan, bring to the boil, cover and simmer for approx. 10 mins. until soft.
Distribute the Mostbröckli over the roesti, serve together with the pear compote.