Preheat the oven to 325 degrees . Season the beef with salt and pepper, then toss with the flour to coat. In a wide, shallow, flameproof casserole, heat 1 tablespoon olive oil over medium heat. Add half of the beef and cook, turning occasionally, until browned, 7 to 8 minutes. Transfer to a plate and repeat with the remaining beef and olive oil.
Add the onion, rosemary, bay leaf and paprika to the pot and cook, stirring, over medium-low heat, until the onion is softened, about 5 minutes. Stir in the wine, scraping the bottom of the pan, and simmer until slightly reduced, about 1 minute. Stir in the beef broth, return the meat and any juices to the pot and bring to a boil, stirring occasionally. Cover the pot, transfer to the oven and bake until nearly tender, about 1 1/2 hours.
Add the squash to the stew, cover and bake until tender, about 20 minutes. Season to taste with salt and pepper. Increase the heat to 425 degrees and cover with the frozen potatoes. Bake, uncovered, until the top is crisp and golden, about 20 minutes.