Prepare the pork belly: Place the pork belly skin-side up on a wire rack in the refrigerator, uncovered, overnight to dry out the skin. This step ensures extra crispy crackling. The next day, preheat your oven to 200 degrees Celsius.
Create the salt crust: Remove the pork belly from the refrigerator and pat the skin dry with paper towel. Brush the skin lightly with water, then pack the coarse salt neatly and evenly over the entire skin surface, creating a thick salt crust. Place the pork belly on a baking tray lined with baking paper.
First bake: Roast the pork belly for 20 minutes. The salt crust will harden and draw out moisture from the skin. After 20 minutes, carefully remove the salt crust by lifting or breaking it away from the skin. Discard the salt. Brush the skin with white vinegar to help achieve maximum crispiness.
Second bake: Return the pork belly to the oven and roast for another 20-30 minutes until the skin is beautifully crispy and golden.
Make the glaze: While the pork is roasting, prepare the maple mustard glaze by whisking together the Dijon mustard, maple syrup, apple cider vinegar, crushed garlic, salt and black pepper in a small bowl.
Final glaze: During the last 10 minutes of cooking, brush half of the maple mustard glaze over the pork belly, allowing it to caramelise slightly.
Rest and serve: Remove the pork belly from the oven and let it rest for 5-10 minutes. Slice into portions and serve with the remaining maple mustard glaze drizzled over or served on the side.