1-1/2 tsp paprika
1-1/2 tsp dried oregano
1-1/2 tsp ground cumin
1-1/2 tsp salt
1-1/2 tsp ground black pepper
1-1/2 tsp garlic powder
1-1/2 tsp onion powder
1-1/2 tsp ground turmeric
1 pinch cayenne pepper, or to taste (optional)
4 pounds whole pork belly
2 Tbsp lemon juice
Combine paprika, oregano, cumin, salt, pepper, garlic powder, onion powder, turmeric and cayenne pepper in a bowl, rub onto the non-fat side of pork belly. Cover with plastic wrap and refrigerate at least 2 hours and up to overnight.
Preheat oven to 450 degrees F. Line a rimmed baking sheet with parchment paper.
Remove plastic wrap from pork belly and place pork belly, fat side-up, on the prepared baking sheet. Make shallow cuts into the fat of the pork belly in a checkered pattern. Rub lemon juice into the fat.
Roast in the preheated oven until fat begins to brown, 30 to 40 minutes. Reduce oven heat to 350 degrees F and continue cooking until fat is crispy, about 1 hour more. Remove from oven and let rest 10 to 15 minutes before slicing.