Step 1: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease it.
Step 2: In a large skillet, heat the olive oil over medium-high heat. Add the sliced onions and bell peppers.
Step 3: Sauté the vegetables for 5-7 minutes until they are softened and starting to brown. Season with salt, pepper, and garlic powder.
Step 4: Lay the beef slices flat on a clean work surface. If using thin ribeye, you may need to sear the meat for 30 seconds per side in the skillet first.
Step 5: Place one slice of provolone cheese on top of each beef slice. If the cheese is too large, fold it to fit.
Step 6: Spoon a portion of the sautéed peppers and onions onto the center of each cheese-topped beef slice.
Step 7: Carefully roll the beef around the filling and secure each roll with a toothpick.
Step 8: Place the roll ups on the prepared baking sheet and bake for 5-10 minutes, or until the cheese is completely melted and bubbling.
Step 9: Remove from the oven and serve immediately while warm.