Place your pork butt on a baking sheet, lather with yellow mustard all over and generously season all sides with your favorite BBQ seasoning in order to completely cover the roast.
Place them in the fridge, uncovered, for at least 4 hours but ideally overnight.
Preheat your smoker to about 250F. Add some wood chips or wood chunks if desired for extra smoky flavor.
Pull your pork butt out and place on the smoker to cook until 165F internal (about 4-6 hours).
Once the pork butt has hit the temperature, pull it out and place in a large foil bin.
Add your pork fat and light beer to the foil bin. The liquid in the bin should come past 50% of the pork butt’s height, so add more or less if necessary.
Tightly cover your bin with foil and place back on the smoker at 250F to smoke until the meat is tender to probe and shreddable (another 3-4 hours).
Once the pork butts are done, pull them off and let them rest for 30 minutes.
Preheat your grill to medium high temperature (around 375F) for direct cooking.
Next, grill your corn over the high heat for 6-8 minutes until fully cooked and slightly charred.
Pull off the grill and slice the corn off the cob. Add the corn to a bowl and mix together with all of the other ingredients for the Grilled Corn.
Finally, mix in a bowl all the ingredients for the Elote Sauce.
Next, pull your pork butt.
Then, add a cast iron skillet with the tortillas, shredded cheese and a small handful of pulled pork to toast for 1-2 minutes.
Pull off and build your taco. Start with the grilled corn and then the elote sauce on top. Serve and enjoy!