Begin by making the Pulled Pork: Preheat the oven to 300 degrees.
At the bottom of a large Dutch oven, place the onions. Mix all the spices together and rub them all over the pork. Place the pork butt on top of the onions, fat side up. Add the chicken stock to the bottom of the pot.
Bake, tightly covered, for five hours. When the pork is done, shred it with two forks and stir in the sugar. You'll only need about a quarter of the pork for this recipe. Freeze the rest for other meals.
While the pork cooks, make the barbecue sauce, cilantro crema and the pineapple salsa.
For the Bourbon Barbecue Sauce: Melt the butter in a three quart saucepan, and cook the onion and garlic until softened. Then, add the rest of the ingredients, and simmer uncovered for 20 minutes. Stir this into the pork you're using for the tacos.
For the Pineapple Salsa: Simply combine all the ingredients in a bowl.
For the Cilantro Crema: Mix the ingredients together in a small bowl.
To Assemble the tacos: In a cast iron skillet, on medium heat, toast up each tortilla on both sides. Fill the tortillas with some pork, some salsa and some crema.