Preheat Oven and Prep Ingredients: Preheat your oven to 350°F. While it's warming up, slice and dice all your ingredients – onions, bell peppers, and mushrooms.

Cook the Veggies: Heat the olive oil in a large skillet over medium heat. Add the sliced onions, bell peppers, and mushrooms. Sauté till the veggies are softened, about 5-7 minutes. Season with salt and pepper to your taste.

Warm the Meat: Push the vegetables to one side of the skillet and add the roast beef on the other. If you're using leftover turkey, just shred it and add it in the same way. Heat until warmed through, stirring occasionally.

Prepare the Slider Rolls: In a small bowl, combine the mayonnaise, Dijon mustard, and Worcestershire sauce. Spread this mixture on the bottom half of each slider roll.

Assemble Sliders: Lay the bottom half of the rolls on a baking sheet. Layer the cooked veggies and meat on top. Cover with slices of provolone cheese and then top each slider with the other half of the roll.

Bake: Place the sliders in the oven and bake until the cheese is melted, around 12-15 minutes.

Serve: Remove from the oven and serve immediately. Enjoy your Black Friday Philly Cheesesteak Sliders warm.