Prep the steak and aromatics: Pat the steak dry with paper towels (dry surfaces sear better). Season both sides generously with 3/4 tsp salt and 1/2 tsp black pepper. Make the chipotle-style rub by mixing the ground cumin, chili powder, minced garlic, and the zest of 1 lime in a small bowl. Rubbing the spices onto the meat creates a concentrated flavor crust when seared.

Marinate briefly (optional but recommended): Drizzle 1/2 tablespoon olive oil over the steak and rub the spice mixture into both sides. Squeeze half of the lime juice over the steak, then let it rest 20 minutes at room temperature or refrigerate up to 2 hours. A brief acid contact helps tenderize and flavor the meat; don’t over-marinate or it can begin to break down the surface proteins too much.

Make the cauliflower rice: Remove the core and large stems from the cauliflower and cut into florets. Pulse in a food processor in 2–3 quick bursts until the texture resembles coarse crumbs or rice — don’t over-process or it will turn mushy. If you don’t have a food processor, grate the cauliflower on the large holes of a box grater.

Dry and season the cauliflower: Spread the riced cauliflower in a single layer on a clean kitchen towel or paper towels and press to absorb excess moisture. This step keeps the cauliflower rice fluffy and allows it to brown instead of steaming in the pan.

Roast the peppers and onion: Preheat the oven to 450°F (230°C). Toss the sliced bell peppers and red onion with 1/2 tablespoon olive oil, a pinch of salt, and a few grinds of black pepper. Spread on a rimmed sheet pan in a single layer and roast 12–15 minutes, turning once, until edges are caramelized and slightly charred. High heat encourages Maillard browning for sweet, smoky flavor.

Sear the steak for a charred crust: Heat a heavy skillet or cast-iron pan over medium-high to high heat until very hot (a drop of water should sizzle away immediately). Add the remaining 1/2 tablespoon of olive oil and swirl. Add the steak and sear without moving it 3–4 minutes until a deep brown crust forms, flip and sear the other side 3–4 minutes for medium-rare (internal ~130–135°F / 54–57°C). Searing develops the flavorful browned crust that defines carne asada.

Rest and finish the steak: Transfer the steak to a cutting board and let it rest 8–10 minutes (resting lets the juices redistribute so they don’t spill out when you slice). While it rests, squeeze the remaining lime over it, and sprinkle with half the chopped cilantro to infuse fresh brightness.

Cook the cauliflower rice: While the steak rests, warm a large nonstick or cast-iron skillet over medium heat. Add the riced cauliflower and spread into an even layer. Cook undisturbed 2–3 minutes to let moisture evaporate and the bottom brown slightly, then stir and cook another 4–5 minutes until tender with light golden flecks. Season with 1/4 tsp salt, 1/8 tsp pepper and the remaining lime juice (taste as you go). Browning adds nuttiness and prevents a raw cauliflower taste.

Combine and warm roasted peppers: When the cauliflower is nearly done, add the roasted peppers and onions to the pan for 1–2 minutes just to warm and marry flavors. Stir in the remaining chopped cilantro. This step integrates the sweet-roasted vegetables into the rice for even bites.

Slice the steak against the grain: Identify the grain (the direction the muscle fibers run) and slice thinly across the grain at a slight diagonal into 1/4" slices. Slicing against the grain shortens the muscle fibers and makes every bite tender. Arrange slices over the cauliflower rice and roasted peppers.

Plate and finish with toppings: Spoon the sour cream in small dollops over the steak or thin with a teaspoon of water and drizzle. Add additional lime wedges, a pinch of flaky sea salt or a crack of black pepper, and a sprinkle of cilantro and lime zest for brightness. Serve immediately so the steak remains warm and the cauliflower retains its texture.

Storage and reheating: Store leftover components separately (steak slices and cauliflower rice/veggies) in airtight containers in the refrigerator for up to 3 days. Reheat steak gently in a 300°F oven covered with foil 6–8 minutes or briefly in a hot skillet; reheat cauliflower rice in a skillet to revive texture. Avoid microwaving steak too long or it will overcook and toughen.