Boil salted water in a large pot, add elbow macaroni and cook until al dente, about 7-8 minutes. Drain and set aside.

In a skillet, heat olive oil over medium-high heat. Season steak with salt and pepper, add to skillet, and cook for 5-7 minutes until browned. Remove and set aside.

In the same skillet, add diced bell peppers and onions. Sauté over medium heat for 4-5 minutes until softened.

Lower heat and pour in whole milk, then add garlic powder, onion powder, and shredded cheese. Stir until cheese melts and mixture is smooth.

Combine cooked steak and macaroni with cheese sauce, folding gently until coated.

Serve hot in bowls, garnished with chopped green onions.