Prepare the steak and aromatics: Pat the 350 g skirt/flank steak dry with paper towels (dry surface browns better). Season both sides with 3/4 tsp sea salt, 1/4 tsp black pepper, 1 tbsp chili powder and 1 tsp cumin—rub the spices in so they cling. Let sit at room temperature for 10–15 minutes while you prep vegetables. Resting at room temperature shortens searing time and helps even cooking.

Rice the cauliflower and drain moisture: Trim and core the cauliflower, then pulse in a food processor to make ~4 cups riced cauliflower. Spread it on a clean towel and press gently to remove excess surface moisture—drier riced cauliflower sautés into fluffy grains rather than steaming soggy clumps.

Slice the vegetables: Cut 1 large onion into 1/3" (8 mm) slices and 2 bell peppers into 1/3" strips. Thin even slices cook evenly and develop those characteristic sweet, caramelized edges.

Sear the steak (high heat for a quick crust): Heat 1 tbsp olive oil in a large heavy skillet or cast‑iron pan over high heat until shimmering but not smoking. Add the steak in an even layer (work in batches if your pan is small) and sear 2–3 minutes per side for medium‑rare (internal temp ~130–135°F / 54–57°C). A hot pan creates a Maillard crust that delivers intense flavor—avoid moving the steak around while it’s searing. Transfer steak to a cutting board and tent loosely with foil to rest (this lets the juices redistribute).

Quickly slice the rested steak: After 5–7 minutes resting, slice the steak thinly across the grain. Cutting against the grain shortens the muscle fibers and yields tender bites—important for skirt/flank which can be chewy if sliced incorrectly.

Sauté onions and peppers to develop sweetness and char: In the same hot pan (add the remaining 1 tbsp oil if dry), reduce heat to medium‑high and add the sliced onion and peppers. Cook 6–8 minutes, stirring occasionally, until edges are softened and charred in places. Add minced garlic in the last 60 seconds to avoid burning. Using the same pan captures beef fond (browned bits) left behind and builds layered flavor.

Season the veg: Sprinkle 1/2 tsp salt, a pinch of black pepper and a light dusting (about 1/2 tsp) of chili powder over the vegetables while they cook—this helps the vegetables release moisture and caramelize evenly, and keeps the fajita flavor consistent.

Make the cauliflower rice: Push the veg to the side of the pan (or use a second large skillet) and add the riced cauliflower. Over medium heat, sauté the cauliflower for 5–7 minutes until just tender and slightly toasted—stir occasionally. Add a squeeze of lime and 1/4 tsp salt toward the end to brighten flavor. Toasting the riced cauliflower concentrates flavor and prevents it from becoming watery.

Warm the steak with the veg: Return the sliced steak to the pan with the vegetables for 1–2 minutes to warm through and marry flavors—this short finish prevents overcooking while letting spices and fond mingle.

Assemble the bowls: Divide the cauliflower rice between 3 bowls. Top each with a portion of the steak, a generous scoop of onions and peppers, sliced avocado, and a sprinkle of chopped cilantro. Serve immediately with lime wedges for squeezing. The layering keeps textures distinct—cool avocado and lime cut through the warm, smoky steak.

Finishing touches: Taste and adjust salt, pepper and lime. If you want a touch of extra richness, drizzle 1 tsp olive oil or a tiny knob of ghee on the cauliflower rice before serving.