Preheat the oil and butter in a large nonstick skillet over medium heat. Add potatoes, toss to coat with oil, and place a lid on the pan. Allow the potatoes to cook covered for 10 minutes.
Remove the lid and increase the heat to medium high. Add onion and bell pepper. Cook for 15 minutes, stirring occasionally, until the potatoes and vegetables turn golden brown.
Add the parsley and garlic; cook for 2 minutes. Season with salt and pepper. Sprinkle with Parmesan and serve immediately.
Recipe Notes
Adapted from The Comfort of Cooking (www.thecomfortofcooking.com)