Preheat oven to 350°F. Measure 1/4 cup tomato sauce, brown sugar and mustard into small bowl; set aside for topping. Add remaining tomato sauce, Ground Beef, bread crumbs, egg, onion, Worcestershire, thyme, garlic salt and pepper to large bowl; mix thoroughly but lightly.
Shape beef mixture into 8 x 4-1/2-inch loaf on rack in broiler pan. Spread topping over meatloaf. Bake in 350°F oven 1 hour or until instant-read thermometer inserted into center registers 160°F.
Let stand 10 minutes before cutting. Cut into slices.
Four-Pepper Meatloaf Variation: Prepare meatloaf as above, adding 1/3 cup finely chopped green bell pepper, 1/4 teaspoon ground red pepper and 1/4 teaspoon ground white pepper to Ground Beef mixture.
Picadillo-Style Meatloaf Variation: Prepare meatloaf as above, omitting thyme and adding 1/3 cup finely chopped green bell pepper, 1/4 cup raisins, 1 teaspoon ground cumin and 1/2 teaspoon dried oregano leaves, crushed, to Ground Beef mixture.
Nutrition information per serving: 216 Calories; 80.1 kcal Calories from fat; 8.9 g Total Fat; 3.5 g Saturated Fat; 0.21 g Trans Fat; 0.7 g Polyunsaturated Fat; 3.6 g Monounsaturated Fat; 106 mg Cholesterol; 467 mg Sodium; 10 g Total Carbohydrate; 1.1 g Dietary Fiber; 24.7 g Protein; 3.5 mg Iron; 464 mg Potassium; 5.8 mg Niacin; 0.4 mg Vitamin B6; 2.2 mcg Vitamin B12; 5.8 mg Zinc; 23.5 mcg Selenium; 102.8 mg Choline;