Chop up vegetables. In a skillet, warm 1-2 tbs of olive oil or butter & add vegetables. Cover with lid and cook on medium heat until softened, stirring occasionally. Season to taste.
Cut steak into thin slices. In a skillet, cook meat over medium heat for 3-4 minutes on each side or until desired. Season to taste.
Layer 2 pieces of cheese on both sides of the bun. Toast bun in the oven or toaster oven for ~3 minutes.
Combine vegetables & meat in one skillet, stir together on low heat.
Using a large spoon, add cooked ingredients to inside of bun. Enjoy while warm!