Mix a marinade with sherry, oil, cornstrach and paprika powder. Press garlic into marinade and season with salt and pepper. Cut filets into bite-size cubes and marinade them about 45 minutes.
Skewer filet cubes, alternating with mushrooms. Fry them on every side about 5-10 minutes. Remove and keep warm. Pour marinade and soup into the pan and let all simmer until sauce is thickened. Season to taste with salt and pepper.