Pull the main vein out of each of the Collard leaves and discard. Roll the leaves up 2 or 3 at a time and cut across the leaves giving you about ¾ of an inch strips. Heat stock pot on med high heat and add the oil. When oil shimmers or is fragrant, add the Pancetta. Fry until most of the Pancetta is crisp but not burned. Add the greens and combine to coat. Cover and cook for 1 minute. Add stock then hot sauce and cover. Let simmer for about 30 minutes or until tender. Stir about 3 times during the 30 minutes and adjust temperature. If for some reason it looks like it's drying out, add a bit more stock and check the heat. Add salt and pepper to taste. Serve hot and add a little of the “liqueur†for those who like it...like me!