Heat large nonstick skillet over medium heat until hot. Add Ground Beef, mushrooms, garlic and thyme; cook 8 to 10 minutes, breaking Ground Beef into 3/4-inch crumbles and stirring occasionally. Pour off drippings, as necessary.
Stir noodles and broth into beef mixture. Bring to a boil. Cover and cook 9 to 10 minutes or until noodles are tender, stirring twice. Stir in peas; continue cooking, uncovered, 3 to 5 minutes or until peas are heated through, stirring occasionally.
Remove from heat; stir in 1/4 cup sour cream and mustard. Season with salt and pepper, as desired. Garnish with additional sour cream, if desired.
Nutrition information per serving: 327 Calories; 104.4 kcal Calories from fat; 11.6 g Total Fat; 4.8 g Saturated Fat; 0.2 g Trans Fat; 0.6 g Polyunsaturated Fat; 4 g Monounsaturated Fat; 93 mg Cholesterol; 435 mg Sodium; 24 g Total Carbohydrate; 2.2 g Dietary Fiber; 4.3 g Total Sugars; 34 g Protein; 0 g Added Sugars; 43.9 mg Calcium; 4.5 mg Iron; 653 mg Potassium; 0.1 mcg Vitamin D; 0.6 mg Riboflavin; 10.5 mg NE Niacin; 0.6 mg Vitamin B6; 2.8 mcg Vitamin B12; 320 mg Phosphorus; 7.3 mg Zinc; 27.7 mcg Selenium; 118.9 mg Choline;