Begin by trimming the some fat cap off of the meat (if there is one). Using a paring knife, poke 12 1in holes in the meat. Stuff each clove with one peeled clove of garlic.
Mix together the sazon and adobo and rub all over the meat. Allow the meat to rest for 2 hours minimum, up to overnight.
Preheat the oven to 300°
Place chopped onions and celery in the bottom of a large dutch oven or oven safe pot with a lid. Place the pork on top, fatty side on the top.
Place in the oven and cook for 3 hours. Remove the lid and cook an additional 3 hours or until the pork has reached at least 170° or is fall apart tender. Pull and serve
ALTERNATIVELY: After marinating, place the onions, peppers, and meat in a large slow cooker on low for 6 hours. Remove roast from the slow cooker and transfer to a baking sheet and place in the oven under the broiler for 5 minutes or until a dark crust forms.
