Sauté onions in a skillet over medium-high heat. When onions are translucent add garlic and beef.
Reduce heat to low and stir in flour, salt, and paprika. Cook for 5 minutes and then add mushrooms. Sauté mushrooms for 5 minutes then add soup and water.
Simmer for 10 minutes then add sour cream and make sure not to boil. Serve sauce over noodles.