Preheat your oven to 425 degrees F. and line a sheet pan with parchment paper. Toss the broccoli, red onion, and bell peppers with 1/2 tablespoon olive oil, salt, and pepper.
Roast for 15 minutes, stirring halfway, until tender and slightly caramelized.
Season steak cubes with onion powder, salt, and pepper.
Heat a large skillet over medium-high heat and add the remaining 1/2 tablespoon olive oil.
Add the steak bites in a single layer and cook for 2 minutes per side, until browned and cooked to your preferred doneness.
Lower the heat and add the light butter, minced garlic, and Worcestershire sauce to the pan. Stir until the steak is coated and the garlic is fragrant (about 1 minute).
Spoon the steak bites over your roasted vegetables and drizzle with the leftover garlic butter sauce from the pan.