Place the diced potatoes in a large microwave-safe dish with 1 tablespoon of water. Cover and microwave on high for 3 to 4 minutes, or until the potatoes are crisp-tender but not mushy.
Heat the olive oil in a large cast iron skillet over medium heat. Add the diced red bell pepper and red onion, then sprinkle with garlic powder, dried parsley, dried rosemary, and smoked paprika. Season with salt and black pepper to taste and stir to combine.
Cook the vegetable mixture, stirring frequently, for 3 to 4 minutes until the peppers and onions are softened and have developed a bit of color.
Drain any excess moisture from the potatoes and pat them dry with a paper towel. Transfer the potatoes to the skillet and season with additional salt and pepper as desired.
Cook for 6 to 7 minutes, stirring occasionally, until the potatoes are golden brown and crispy on the edges.
Remove the skillet from heat and sprinkle the freshly grated Parmesan cheese over the top. Cover the skillet briefly until the cheese melts, then serve immediately.