Sweet Potato Cottage Pie

1-1/2 pounds sweet potatoes (about 2 large)
1 tablespoon olive oil
1 cup chopped onion
1/4 cup chopped celery
1 teaspoon finely chopped garlic (1 large clove)
1 pound ground beef, 90% lean
1 can (15 ounces) tomato sauce
1 tablespoon Worcestershire sauce
1-1/2 teaspoons fresh thyme or 1/2 teaspoon dried thyme or herbes de Provence, divided
1/2 teaspoon salt, divided
1/2 teaspoon ground black pepper
2 tablespoons butter
1 tablespoon milk

Preheat oven to 350°F. Oil a 6 to 8 cup shallow baking dish.
Pierce sweet potato skins. Microwave until tender, about 4 to 6 minutes; cool.
In large skillet, heat oil over medium heat. Add onion and celery; cook and stir until tender, about 5 minutes. Add garlic; cook and stir 1 minute.
Add beef; cook and stir until it just begins to brown.
Stir in tomato sauce, Worcestershire, 1 teaspoon of the thyme and 1/4 teaspoon of the salt and pepper; bring to a boil. Transfer to baking dish, spreading evenly.
Scoop sweet potato from skins into medium bowl. Add butter, milk, remaining ½ teaspoon thyme and ¼ teaspoon each salt and pepper. With electric beater, beat until smooth. Spread over meat in baking dish.
Bake until bubbly, about 20 to 25 minutes.

Number of servings (yield): 4-6

Nutrition per serving: 386 calories; 34 g carbohydrates; 6g fiber, 15 g total fat