Prepare steaks and vegetables. Heat 2 Tbsp. oil/butter/margarine in skillet. Sauté onion until transparent; set aside.
Add remaining 2 Tbsp. oil/butter/margarine to skillet. Sauté mushrooms for 3 minutes. Season with nutmeg, salt and pepper. Whisk yogurt with lemon juice and add to the mushrooms. Heat, do not boil. Add beef strips and onion to the skillet. Heat through and serve over noodles or rice.