Finely chop onion and place in medium to large skillet. Slice mushrooms and add to skillet. Saute onions and mushrooms in oil for 2 minutes only.
Cut beef into 1-inch cubes. Add beef to onions and mushrooms and saute beef until cooked all the way through (internal temperature of beef should be 160 degrees Fahrenheit). Turn to brown evely.
Add yogurt, salt, pepper, nutmeg, basil, and wine to skillet; gently stir in. Heat, but do not boil.