This is a go-to recipe for me, so at this point measurements are done by instinct. Pork shoulder is a delicious and super cheap cut but needs a while to get tender and for the fat throughout it to dissolve. Make ahead of time to use with this Farfalle with Roast Pork and Cherry Tomato Sauce recipe.
Rinse pork shoulder with cold water and pat dry. Trim off excess fat, especially if the butcher left on the skin and fat on one side (which you can use to make pork cracklins in the oven). Make small slits on both sides of the meat and insert the garlic slices inside. Whisk together the citrus juices and spices, salt and pepper.
Put the pork in a plastic container or large sealable plastc bag and pour marinade over. Refrigerate for 1-2 hours (or overnight), turning a couple times so all of the sides get marinated.
Heat the olive oil in a large frying pan. Sear the shoulder on all sides. Put in the slow cooker for 5-6 hours on low.