Pat the flank steak dry with paper towels and slice thinly across the grain into 1/8–1/4" (3–6 mm) strips. Cutting across the grain shortens the muscle fibers and makes the finished beef noticeably more tender.

In a large bowl, toss the sliced steak with 1 tablespoon (15 ml) of the olive oil, 1 tsp ground cumin, 1 tsp chili powder, 1/2 tsp kosher salt (reserve the rest for seasoning the veggies and rice) and 1/4 tsp black pepper. Let sit at room temperature for 10 minutes while you prep the vegetables. The quick marinade helps the spices cling to the meat and starts flavor penetration without needing hours.

Heat a large heavy skillet or cast‑iron pan over high heat until just starting to smoke. Add a thin film of oil (about 1 tsp) if the pan is not well seasoned. High heat is essential here to get a fast sear — that brown crust (the Maillard reaction) gives concentrated flavor and texture to the steak.

Working in a single layer and in 2 batches if needed, spread the steak strips in the hot skillet and sear for 60–90 seconds per side without moving them. You want good contact to form a brown crust; moving them too soon prevents proper caramelization. Transfer seared strips to a plate and tent loosely with foil to rest (this keeps them warm and lets juices redistribute).

In the same hot skillet, add the sliced onions and bell peppers and a pinch of salt. Cook over medium–high heat, stirring occasionally, for 6–8 minutes until the peppers are blistered and edges are charred. If the pan looks dry, add 1–2 teaspoons of olive oil. Cooking the veg in the steak fond (brown bits) left in the pan builds layered flavor — don’t scrape those bits away.

Add the minced garlic to the peppers and onions in the last 30–45 seconds and stir to fragrant — garlic cooks fast and will burn if added too early. Taste and season with the remaining 1/2 tsp kosher salt and a little black pepper as needed. Remove veggies to the plate with the steak and keep warm.

Wipe the skillet lightly (leave any fond) and return to medium–high. Add the remaining 1 tbsp (15 ml) olive oil and the cauliflower rice. If using frozen cauliflower rice, make sure it’s well-thawed and squeezed dry — excess water will make the rice soggy. Spread the rice in an even layer and let it cook undisturbed for 2 minutes to let moisture evaporate and a little toasting occur — toasting adds a nutty flavor and prevents pastey texture.

Stir the cauliflower rice, add the 1 tsp butter (optional) and the juice of half the lime (reserve the other half for finishing). Continue to cook for another 3–4 minutes until the rice is tender but not mushy. Finish with a pinch of salt and freshly ground pepper. The butter provides silkiness and mouthfeel; lime brightens and balances the fat.

Return the steak and peppers to the pan just to warm through for 30–60 seconds, or reassemble directly into bowls. Taste and adjust seasoning — a squeeze of lime over the steak and a sprinkle of chopped cilantro wakes up the whole bowl.

To build each bowl: divide the warm cilantro‑lime cauliflower rice between 2 bowls, mound the charred peppers and onions alongside, fan slices of rested steak on top, and finish with sliced avocado, an extra squeeze of fresh lime, and a generous sprinkle of chopped cilantro. Serve immediately. Resting the steak and arranging components separately preserves textures (warm rice, juicy beef, creamy avocado).