Heat the oil in a large cast iron pan to medium-high heat. Sear the beef a few minutes per side to brown them. Transfer to a slow cooker or crock pot.

Deglaze the pan with a bit of beef broth (or water) and scrape all of the brown bits from the bottom of the pan. Pour it into the crock pot.

Add the paprika, chili powder, chipotles in adobo, beef stock, vinegar, lime juice, onion, garlic, oregano, cumin, bay leaf, and salt and pepper to taste to the crock pot. Stir.

Cook on high for 4 hours, or on low for 6-8 hours, or until the beef is fork tender. It should easily break apart with a fork. It could take a bit longer to cook, depending on your slow cooker.

Shred the beef with two forks.

Prep the ingredients per the instructions above.

Make the guacamole: Mash the avocado with a fork until it is smooth. Stir in the cilantro, garlic, and sour cream. Season with salt and pepper to taste. Refrigerate until ready to serve.

Add the mayonnaise, garlic powder, onion powder, chili powder, salt, lime juice, and chopped cilantro into a small bowl. Stir together until combined. Mix in the corn.

Lightly warm the tortilla shells on both sides in the skillet over medium heat.

Mix the ingredients for the margarita until very well combined. Serve over ice if desired.

Serve: Layer the taco shells with shredded beef; spoon the sauce over top. Garnish with tomato and jalapeño if using. Enjoy with chips, guacamole, street corn salad, and margarita.