Dice potatoes into bite size chunks and boil potatoes until fork tender; let cool. In a separate bowl mix ranch, sourcream, parsley and ½ cup of cheese.
Preheat the oven to 350 deg fahrenheit. Pour potatoes into a 13x9 aluminum pan. Mix in the ranch sauce and bacon (if using). Top with remaining cheese and cornflakes. Pour melted butter over top.
Bake for 30-45 minutes, or until cornflakes are browned and cheese is bubbly. Serve hot.