Light grill or smoker and set up for indirect heat. Add one chunk of oak wood to the coals and establish temperature at 375°F as indicated by a reliable leave-in thermometer.
While the grill is preheating, cut the boneless pork shoulder into two inch cubes.
In a large dutch oven, add all ingredients (leaving out stock, and lard). Mix thoroughly by hand to ensure the pork is evenly coated with the spices.
Add in enough stock to leave about 1/2 inch of the pork above liquid level, and the lard.
Place the dutch oven on the grill over indirect heat, with the lid off the dutch oven. Close the grill's lid and allow the carnitas to smoke and braise for three hours, stirring every hour.
Remove dutch oven from the grill and set aside. Tacos can be assembled with warm corn tortillas and eaten at this point, and they’ll be delicious. For a little something extra, proceed to step 7.
(Optional Step) Skim 2-3 tablespoons of rendered fat off the remaining liquid and place it in a cast iron pan over medium high heat. Then, lightly brown some of the chunks of pork in the heated fat.
Pull pork into bite sized pieces and place on warm corn tortillas. Top with toppings of your choice and serve.