Preparing the Marrow Bones: Preheat your oven to 400°F (about 200°C). Place the marrow bones on a baking sheet and roast for 20 minutes. This step enhances the flavor of the bones and helps to release the marrow.

Simmering the Bones: Transfer the roasted marrow bones to a large pot and add water. Bring to a boil, then reduce the heat to a low simmer. Cover and cook for 3-4 hours to extract the nutrients from the bones and marrow.

Preparing the Pork Belly: While the bones are simmering, prepare the pork belly. In a separate pan over medium heat, cook the pork belly pieces until evenly browned and slightly crisp. This should take about 10-15 minutes.

Combining Ingredients: Once the marrow bones have simmered for 3-4 hours, add the cooked pork belly pieces to the pot. Continue to simmer for an additional hour, allowing the flavors to meld together.

Seasoning: Season the soup with salt, adjusting according to your taste preferences.

Finishing the Soup: After the soup has simmered with both the marrow bones and pork belly, remove it from heat. You may choose to strain the broth for a clearer soup or leave it as is for a more rustic feel. If desired, scoop out the marrow from the bones to stir back into the soup or serve on the side.

Serving: Ladle the hot soup into bowls, ensuring each serving gets pieces of pork belly and, if preferred, marrow.