Toss the sliced onions and peppers with 1 tablespoon of the oil and 1 tablespoon of the seasoning. Grill on a grill mat, flipping halfway through for about 10 minutes. Transfer the veggies to a serving platter.
Drizzle the remaining tablespoon of oil over the steak and sprinkle with the seasoning. Turn the grill to high. Grill the steak for 3-4 minutes per side.
Let the steak rest for 5 minutes before slicing against the grain. Serve with the grilled peppers, onions, and your favorite toppings.
Nutrition: This recipe makes 8 servings. Each serving has 7 NET carbs when you use half a pound of onions and peppers.