Lightly score the fatty side of pork with the tip of a knife slicing in a diagonal and creating a diamond-shaped pattern; season all over with salt.
Coarsely grind Whole Cloves, Coriander, Oregano, and Mustard Seeds in a spice mill or with mortar and pestle, set aside.
Heat the Olive Oil in a small saucepan over low heat; add minced garlic and cook, stirring, until fragrant, about 5 minutes. Stir in Orange Zest, Paprika, and reserved spice mixture. Remove from heat and let cool for 5 minutes.
Rub the marinated all over pork. Using kitchen twine tie around pork at 1″ intervals. Wrap tightly in plastic wrap or place in a Ziplock bag and chill for at least 8 hours.
Remove from fridge and let the pork sit at room temperature for 1 hour before cooking.
Preheat the oven to 375 ℉ degrees. Unwrap pork, place on a rack set inside a roasting pan, and roast until golden brown, 40 to 50 minutes. Reduce heat to 300 ℉ degrees and continue to roast until meat is very tender, 1 1/2 to 2 hours more.
Transfer pork to a cutting board and let rest 30 minutes before slicing.