01 - Combine olive oil, lime juice, garlic, cumin, chili powder, smoked paprika, salt, and black pepper in a bowl. Add beef and toss to coat evenly. Marinate for at least 15 minutes, up to 2 hours refrigerated for best flavor.
02 - Heat a large skillet or cast-iron pan over medium-high heat. Add a drizzle of oil if needed.
03 - Add marinated beef in a single layer. Sear for 2–3 minutes per side until browned and just cooked through. Remove beef from pan and set aside, keeping warm.
04 - In the same pan, add sliced peppers and onion. Sauté for 5–7 minutes, stirring occasionally, until vegetables are softened and slightly charred.
05 - Return beef to skillet, tossing with vegetables to combine and heat through.
06 - Warm tortillas in a dry skillet or microwave.
07 - Serve beef and vegetable mixture in tortillas. Top with cilantro, squeeze of lime, and favorite toppings.