Set out chipotle powder, ground cumin, achiote paste, Mexican oregano, cayenne, garlic, sugar, kosher salt, apple cider vinegar and ancho chile powder (clockwise from top).
Toss Cubed Pork with Spices
Place a large bowl, pusher and assembled meat grinder attachment fitted with a fine grinding plate in the freezer. In another large bowl, toss the pork shoulder, fatback, ancho chile powder, salt, garlic, chipotle powder, oregano, cumin, sugar and cayenne together until all the pork is completely coated with the spice mixture.
Cover tightly with plastic wrap and place in the freezer to chill for up to 1 hour (you want the meat very cold but not frozen solid).
Mix together the vinegar and achiote paste in a small bowl with a fork until smooth, and keep it in the refrigerator.
Prepare the Ice Bath
When ready to grind the meat, fill a large bowl with ice water and then nest the chilled bowl from the freezer into it. This will help keep everything cold (and the sausage tender).
Grind the Fatback + Shoulder Meats
Working quickly, grind the pork into the chilled bowl in the ice bath with the machine at medium-high speed. After the pork is ground, cover the bowl with plastic wrap and place it in the freezer until very cold, about 20 minutes (at 45 degrees F, the fat begins to melt and can affect the texture of the sausage).
Add the Achiote
Remove the ground pork from the freezer and add the chilled achiote mixture and any remaining spice mixture. (The achiote will stain your hands, so wear gloves if you have them.)
Knead the Meat Until It's Sticky
Using clean hands (wear gloves to prevent staining) or the paddle attachment of a stand mixer, knead or mix the pork until a sticky mass forms, about 2 minutes by hand or 1 minute using a stand mixer at medium speed. Wrap the chorizo tightly in plastic wrap and refrigerate from 24 hours up to 3 days before using (flavors will develop as the chorizo rests). The chorizo can also be formed into patties and frozen for up to 3 months.
Fry the Meat
In a large nonstick skillet over medium-high heat, cook 1 pound (about a third) of the chorizo, breaking it into small pieces with the side of a wooden spoon. Stir occasionally until cooked through and browned, 5 to 7 minutes.
Taco Time!
Serve the cooked chorizo on warm corn tortillas with shredded cabbage, pickled red onions, crumbled queso fresco, cilantro leaves and lime wedges.
