In a large bowl, combine 2 tbsp olive oil, Worcestershire sauce, paprika, garlic, oregano, salt, pepper, and onion powder. Add the steak, onions, red and yellow bell peppers, and mushrooms, tossing to coat.
3 Tablespoons olive oil, 1 1/2 pounds flank steak, 1 medium red bell pepper, 1 medium yellow bell pepper, 1 small red onion, 4 cloves minced garlic, 1 1/2 teaspoon smoked paprika, 1 teaspoon onion powder, 2 teaspoons dried oregano, 1 1/2 teaspoon sea salt, 1 teaspoon black pepper, 2 Tablespoons Worcestershire sauce, 8 ounces sliced mushrooms