Crispy, blistered and golden brown, old-fashioned fried pork skins come from applying a combination of three cooking techniques to pork belly: braising, confiting and frying. Braising the pork, or cooking it low and slow in liquid, renders the copious amounts of subcutaneous fat that get in the way of crisping the skin. Confiting gently heats the pork skin in an ethereal blanket of its own rendered fat, adding layer upon layer of flavor to the soon-to-be-crisped skin. Frying the pork in the rendered fat does what frying does best: crisping the skin to crackling bliss.
Mix together a 2-1 ratio of baking soda to iodized salt in a bowl with a whisk. Rub the mixture deeply into the skin of the pork belly. Use ratio of 2 teaspoons baking soda to 1 teaspoon salt per pound of pork belly no matter how many cracklings you're preparing. Disperse the mixture evenly over the skin, from edge to edge and corner to corner.
Set the pork belly skin-side up on a wire rack set on top of a rimmed baking sheet or dish. Place the pork belly in the refrigerator uncovered and let it sit 12 to 24 hours.
Remove the pork belly and slice it into 1-inch pieces about 1/3 to 1/2 inch thick. Place the diced pork belly in a heavy-bottomed frying pan.
Cover the pork belly with about an inch of cold water and place it on the stove over low heat. Add a pinch of salt to the water and let the pork cook uncovered for about 3 or 4 hours.
Turn the pork pieces over in the water every 30 to 45 minutes with a slotted spoon. Turn the heat up to medium-high when the water cooks off and only skin and rendered pork fat remain in the pan.
Fry the pork skins in their fat for about 4 or 5 minutes, or until golden brown and crispy. Remove the pork skins from the pan using a slotted spoon and place them on a plate lined with paper towels.
Blot the top of the pork skins with paper towels to remove the excess oil and place them in a mixing bowl. Add seasonings to taste, such as smoked paprika, salt, chili powder, to name a few, and toss to coat. Keep the pork skins on a plate at room temperature so they maintain their crispness.
Baking soda is optional, but it does help the pork skins crisp and bubble with more fervor.