Prepare the barbacoa beef in the slow cooker following this recipe: https://supersafeway.com/slow-cooker-barbacoa-beef/
Fajita Veggies
Heat oil in a skillet over medium-high heat and add sliced peppers and onions and cook for 8-10 minutes until soft. Season with salt and pepper. Once cooked, remove from heat and place in a serving bowl.
Cilantro Rice
heat oil and butter in a medium saucepan over medium heat. Add chopped onions and minced garlic and cook until translucent about 2-3 minutes. Add rice to the pan and water and stir until incorporated. Bring water to a boil, then reduce to a low simmer. Cover the pot to cook the rice until it's done - about 10-12 minutes.
Stir the chopped cilantro, lime zest lime juice, salt and pepper into the cooked rice and pour into a serving bowl.
Place the beans in a microwave-proof bowl and heat for one minute until hot.
Place shredded romaine, beans, sour cream, shredded cheese, cooked barbacoa beef, cilantro rice, fajita veggies in individual bowls and let your guests assemble their own bowls.