Instructions:
- Prepare the Seasoning: In a small bowl, thoroughly whisk together all dry seasoning ingredients (Chili powder through Cornstarch). Set aside.
- Prep the Steak: Slice the steak thinly against the grain into strips about 1/4-inch thick.
- Marinate: In a large bowl, combine the steak strips with 3 Tbsp of the prepared seasoning blend, olive oil, and fresh lime juice. Toss well to coat. Let this sit at room temperature for at least 15 minutes or up to 4 hours refrigerated.
- Prep Veggies: Slice the peppers and onions into uniform strips.
- Sear the Steak: Heat a large cast-iron skillet over medium-high to high heat until nearly smoking. Add half the marinated steak (do not overcrowd the pan). Sear quickly for 2-3 minutes per side until nicely browned. Remove immediately and set aside. Repeat with the remaining steak.
- Sauté Vegetables: Add the remaining 1 Tbsp of neutral oil to the hot pan. Add the onions and peppers. Sauté vigorously, stirring only occasionally, until they are tender-crisp and have developed some charred spots (about 5-7 minutes).
- Combine & Serve: Return the cooked steak (and any accumulated juices) to the pan with the vegetables. Stir quickly to combine everything and heat through for about 1 minute. Taste and add a pinch more salt if needed.
- Final Assembly: Serve immediately, piping hot, with warmed tortillas and your choice of fresh toppings.