Slice the steak as thinly as possible against the grain using a sharp knife. Look for the direction of the muscle fibers and cut perpendicular to them. Slice onions and bell peppers into thin strips. Mince garlic.

Heat a large cast iron skillet over medium-high heat and add olive oil. The pan should be hot enough that a drop of water sizzles and evaporates within 2-3 seconds.

Add sliced steak in a single layer, season with salt, pepper, and Worcestershire sauce. Cook for 3-4 minutes, stirring occasionally, until nicely browned with caramelized edges. Internal temperature should reach 130-135°F for medium-rare. Remove steak and set aside.

In the same pan, add onions and bell peppers. Cook for 4-5 minutes until softened and lightly caramelized - they should be tender but still have a slight bite. Add minced garlic and cook for 30 seconds until fragrant.

Divide cooked cauliflower rice, mashed potatoes, or regular rice into serving bowls. Top with the cooked steak and sautéed vegetables.

Sprinkle shredded cheese over the warm mixture and let it melt naturally from residual heat. For extra bubbly cheese, place under broiler for 1-2 minutes, watching carefully to prevent burning. Garnish with fresh parsley before serving.