Toss 1 ¼ pounds peeled and sliced medium Yukon Gold potatoes, 2 tablespoons all-purpose flour, 1 ¾ teaspoons kosher salt, 1 teaspoon garlic powder, ½ teaspoon paprika, and ½ teaspoon black pepper together in a large bowl until the potatoes are evenly coated.
Melt 2 tablespoons unsalted butter in a large cast iron or nonstick skillet over medium heat. Add 1 thinly sliced medium yellow onion and cook until softened, 6 to 8 minutes.
Add the potatoes and stir to combine with the onions. Spread into an even layer and cook, turning and flipping every 2 to 3 minutes, until the bottom layer of onions and potatoes are light brown in spots, 8 to 10 minutes total.
Reduce the heat to medium-low. Add 1 ¼ cups low-sodium chicken broth and cook, turning the potatoes occasionally, until the potatoes are tender and the sauce has thickened, 14 to 16 minutes. Taste and season with more kosher salt and black pepper as needed. Garnish with more black pepper and chopped fresh parsley leaves if using.
