Slowly fry the bacon until crisp. Heat the butter, sauté the onion and chicory with the sugar for approx. 2 mins., add the diced bacon, liqueur and stock, bring to the boil, reduce the heat, cover and simmer for approx. 5 mins. Add the tomatoes, simmer uncovered for approx. 1 mins., season. Stir in the lemon juice and thyme, scatter over the Sbrinz cheese.