Crush the garlic in a pilón. If you don't have a pilón (shame on you!) crush the whole garlic with the side of a wide knife then dice the pieces. In a small bowl mix together the garlic, salt, pepper, oregano, and olive oil. Mix well.
1. Wash the meat and pat dry.
2. With a sharp knife cut the fat away from the meat, leaving an edge attached and keeping it all in one piece. Start at the wide end and go to the narrow end. You don't have to separate it completely - just leave enough still conected so that you can flip the fat over to the side while you season the meat itself. The fat will be placed over the seasoned meat and will cook over the meat giving it more flavor. Season the side of the fat that goes over the meat with a bit of the seasoning also - just that one side by running your hand on it. The other side - the top - should only have salt.
3. Make very deep slits all over the meat and season the meat making sure that seasoning goes into all the slits. Put the fat back over the meat to look the same as before it was cut and sprinkle it with salt.
4. Refrigerate the shoulder, covered with plastic wrap, for 24 hours (if you are short on time bake at this time)
5. Let the meat get back into room temperature before cooking, if it was refrigerated. (About one hour).
6. Place the meat in a deep pan with the fat side up. There will be a lot of grease so be sure to use a deep pan that is at least 2" deep. The fat side up will make nice crunchy "cueritos." Do NOT cover with foil.
7. Preheat the over for at least 30 minutes before placing the meat inside. Cook in a 400º oven for one hour, then reduce temperature to 300º for about 4 hours or so - DO NOT TURN MEAT. When the meat is done, you can prick it on the side witha fork to see if it shreds. If the "cuerito is not crispy enough for your satisfaction, then leave it in the oven and raise the temperature again to 400º and cook another 15 or so until it is crispy. It will crisp fast so keep your eye on it.
8. Remove the meat from the oven and let it rest on the counter for about 20-30 minutes before carving.
9. To carve, remove the cuerito completely and set aside. Carve the meat and then cut the cuerito into pieces and place over the meat.
If you're going to take this to a party put it in an oven-safe container and put it back in a 200º to keep it warm, DON'T COVER IT because the crispy cueritos will get soft if you do. Cut the cuerito and serve meat with a piece of cuerito on each place. Enjoy!
Tips . . . If using a meat thermometer, it will be ready when it reaches 185ºF.