In a large pan, heat oil and add in onions and green peppers. Cook over medium high heat, stirring occasionally until peppers and onions have softened.
Next, add shaved steak, Worcestershire sauce, garlic powder, and salt and pepper. Cook steak, breaking it apart with two forks to prevent steak from clumping. Cook until the steak is no longer red. Set pan to the side.
Slice sweet rolls in half horizontally, while keeping the 12 pack of buns intact. Place onto a baking sheet. Spread steak mixture over the bottom half of the buns, evenly. Top with cheese slices and the top half of the buns.
In a small bowl, mix together melted butter, dried thyme, and Worcestershire sauce together. Brush butter mixture generously over the top of the buns.
Place sliders in the oven and bake for 17-20 minutes or until the top of the buns are golden and the cheese has melted. Serve and enjoy