Cut the skirt steak into bite-sized pieces.
Cut the onion, bell peppers, and broccoli into bite-sized pieces.
Heat olive oil in a pan and sear the skirt steak over high heat.
Once the surface of the meat is cooked, add the vegetables and stir-fry together.
Season with salt and pepper.
Add steak sauce and a little butter, and stir-fry until well combined.
Plate and serve.