I've always loved fried potatoes with onions, the way my mother used to make them. This recipe is similar but different at the same time.
Recipe: Eating Well magazine
Place potatoes in a large pot of cold water, cover and bring to a boil over high heat. Uncover and reduce heat to maintain a simmer. Cook just until tender, 5 to 10 minutes (should be firm but tender enough to spear with a fork). Drain and return to pot. Place over the still-warm burner to dry, about 5 minutes.
Divide 3 Tbsp. oil between 2 rimmed baking sheets, tilting to coat. Place the pans in a preheated 425º oven to heat for 5 minutes.
When the potatoes are dry, drizzle with the remaining 2 Tbsp. oil. Sprinkle with 1/2 tsp. salt and 1/4 tsp. pepper. Gently toss until coated. Add onions and gently turn with your hands to coat, trying not to break them up.
Arrange the potatoes and onions, cut side down, on the hot baking sheets. Roast until browned and crisp on the bottom, 10 to 15 minutes. Turn the vegetables with tongs and switch the pans back to front and top to bottom. Roast until browned and crisp on the other side, 10 to 15 minutes more. Remove from heat and sprinkle with rosemary and the remaining 1/2 tsp. salt and 1/4 tsp. pepper.