If using a slow cooker or stovetop, saute the onions first on slow-cooker-high or stovetop-med-high, then add the rest of the ingredients and set to low heat for 4-6 hours, until the beef is tender and shreddable. Check back every hour or so to make sure you have enough liquid, and add beef broth as necessary.
Add marinade ingredients to the blender. When the peppers are done soaking, hold them by the tip over the sink and use scissors to cut the stem off and allow the seeds to fall out, then add to blender. Blend into a smooth paste and rub all over the beef. Marinate for a minimum of two hours or up to overnight.
Set your Instant Pot on saute high. Add 1-2 tbsp oil, then saute the onions until golden and translucent (6-8 minutes). See notes for stovetop or crockpot instructions.
Add the meat with the marinade, bay leaves, and cloves to the pot. Barely cover with beef broth, then set to high pressure for 45 minutes.
When the Instant Pot is done, allow a natural release, then remove the meat from the consomé and shred. Spoon some of the consomé onto the beef after you’ve shredded it.
Make the tacos: warm the tortillas and build the tacos: a generous amount of barbacoa beef, and toppings. Enjoy immediately.
