Stack beef Sirloin Tip Steaks; cut lengthwise in half, then crosswise into 1-inch wide strips. Toss with garlic.
Heat 2 teaspoons oil in large nonstick skillet over medium-high heat until hot. Add 1/2 of beef; stir-fry 1 minute or until outside surface of beef is no longer pink. (Do not overcook.) Remove. Repeat with remaining beef. Season with salt and pepper.
Heat remaining 2 teaspoons oil in same skillet over medium-high heat until hot. Add mushrooms; cook and stir 2 minutes or until tender. Remove from heat. Add gravy mix and 1 cup cold water; blend well. Bring to a boil. Reduce heat; simmer 1 minute or until sauce is thickened, stirring frequently. Stir in beef; heat through. Serve over noodles. Pass sour cream.
Nutrition information per serving: 383 Calories; 144 kcal Calories from fat; 16 g Total Fat; 5 g Saturated Fat; 5 g Monounsaturated Fat; 109 mg Cholesterol; 420 mg Sodium; 30 g Total Carbohydrate; 2 g Dietary Fiber; 31 g Protein; 3.7 mg Iron; 6.2 mg Niacin; 0.4 mg Vitamin B6; 1.4 mcg Vitamin B12; 4.7 mg Zinc; 48.7 mcg Selenium;