Pour the stock into a large stock pot with the burner set to high. Add the reserved leek greens and wait for the stock to boil. Immediately reduce heat to a low simmer and cook for 10 minutes. Remove and discard the leek greens, add the potatoes, and simmer until soft, about 20 minutes.
Meanwhile, cut the bacon into lardons (thin strips). Fry in a separate pan over medium-high heat until crisp. Remove the bacon from the pan with a slotted spoon and set aside. Add the leek rings and garlic to the bacon fat in the pan and fry until translucent. Transfer the leeks and garlic to the stock pot, using a ladle to pick up the fat.
Puree the soup smooth with an immersion blender. Add the bacon, the thyme, and then the cream. Mix to combine.
Add 1 tsp of the cider vinegar, mix to combine, and taste the soup. You should taste a difference, though it shouldn’t taste like vinegar. Add the second teaspoon if you like. You can thicken the soup by simmering it for longer or thin it by adding additional stock.
Garnish with cheddar cheese or sour cream and chives, and serve immediately.
If you don’t have a big enough container for the belly, chop it into pieces, and place into a container.
Mix together the garlic, salt, coffee (if using), pepper, maple syrup, and bourbon to make a cure. Massage it into the pork belly and place in the container. Refrigerate for eight days, shaking the container or flipping the belly daily to distribute the cure. You will feel the texture of the meat becomefirmer.
Discard the cure and rinse the pork under cold running water.
Preheat the oven to 200°F. Bake the pork until its internal temperature reaches 150°F, about 1. hours. Allow it to cool.
If smoking, smoke for 4–5 hours until it is dark yellow.
Let the pork cool before wrapping it tightly in butchers’ paper.
Note: The bacon will freeze well if wrapped in butcher paper.
Pro tip: Skip the coffee, maple, and bourbon and substitute 2 tbsp brown sugar and 1 tbsp dried chipotle flakes; or 2 tbsp brown sugar, 1 tbsp smoked paprika, and 10 slices dehydrated apple.