In a small bowl, whisk together the adobo sauce, olive oil, honey, lime juice, garlic powder, salt, and black pepper to make the chipotle marinade.
In a large bowl, combine the sliced flank steak, sliced bell peppers, sliced onion, and chipotle marinade. Toss everything together until the meat and vegetables are evenly coated in the marinade.
Cover the bowl with plastic wrap and let the fajita mixture marinate in the refrigerator for at least 30 minutes or up to 2 hours.
Preheat the oven to 400°F
Spread the marinated fajita mixture out on a sheet pan in a single layer. Drizzle with 2 tablespoons of olive oil and season with salt and black pepper to taste.
Roast in the preheated oven for 15-20 minutes or until the beef is cooked through and the vegetables are tender and slightly charred
Notes
Use a high-quality cut of beef, such as skirt steak or flank steak, for best results.
Marinate the beef in the chipotle sauce for at least 30 minutes or up to overnight to allow the flavors to infuse into the meat.
Use a large sheet pan to ensure that the fajitas cook evenly and have enough room to spread out.
Cut the vegetables into similar sizes to ensure they cook evenly and are done at the same time as the beef.
Don't overcrowd the sheet pan - leave some space between the vegetables and meat to ensure that everything cooks evenly and gets crispy.
Stir the ingredients occasionally to ensure they cook evenly and don't stick to the pan.
Don't overcook the beef - it's best when it's cooked to medium-rare or medium.
Serve the fajitas immediately while they're still hot and crispy.
Don't forget to top the fajitas with some fresh cilantro and a squeeze of lime for added flavor.
Leftovers can be reheated in a skillet over medium heat until heated through or in the oven at 350°F for 10-15 minutes.