Preheat your oven to 425°F (220°C). This high temperature will help achieve that perfect roasted texture.
Cut the cauliflower into bite-sized florets, and slice the bell peppers and sweet onion into strips. Aim for similar sizes for even cooking.
In a large mixing bowl, whisk together the olive oil, lime juice, lime zest, honey, cumin, chili powder, smoked paprika, salt, black pepper, and minced garlic. This mix will infuse the veggies with flavor.
Add the cauliflower, bell peppers, and onion to the bowl with the marinade. Toss until everything is well coated. Allow it to marinate for about 10 minutes for maximum flavor.
Spread the marinated veggies out evenly on a sheet pan. Roast for 20 minutes, stirring halfway through, until they are tender and lightly charred.
After the veggies have roasted, remove the pan from the oven and add the drained and rinsed black beans. Toss everything together and return it to the oven for an additional 5-10 minutes to heat through.
Once everything is perfectly roasted, remove the pan from the oven. Serve the fajita mix in warm tortillas, topped with avocado slices, chopped cilantro, lime wedges, and a sprinkle of cotija cheese and sour cream if desired. Enjoy every bite of your Roasted Cauliflower and Black Bean Sheet Pan Fajitas!