Slice the marbled steak into thin strips against the grain for optimal tenderness. Combine with olive oil, lime juice, minced garlic, and fajita seasoning. Marinate for 15-20 minutes.

Heat a large cast iron skillet over medium-high heat. Add olive oil and sear the marinated steak strips for 2-3 minutes per side until browned.

In the same skillet, add more olive oil if needed, then sauté the bell peppers and red onion for 5-7 minutes.

If using cauliflower rice, sauté it for 3-5 minutes. If using lettuce, arrange it in serving bowls.

Layer your bowl starting with cauliflower rice or lettuce, then sautéed vegetables, and finally the steak strips. Garnish with avocado, sour cream, and lime juice.

Serve immediately and enjoy!