Ghostly Shepherd's Pie

1 lb lean ground beef
1 medium onion, coarsely chopped
2 1/2 cups frozen mixed vegetables
1 can (14 1/2 oz) diced tomatoes with Italian herbs, undrained
1 jar (12 oz) home-style beef gravy
1 3/4 cups water
2 tablespoons butter
1/4 teaspoon garlic powder
1/2 cup milk
2 1/4 cups instant mashed potatoes
1/4 cup grated Parmesan cheese
1 egg, slightly beaten

Heat oven to 375 degrees. Spray 12-inch skillet with cooking spray. Cook beef and onion in skillet over medium heat 8 to 10 minutes, stirring occasionally, until brown; drain.

Set 12 peas (from frozen vegetables) aside for garnish. Add remaining frozen vegetables, tomatoes and gravy to beef mixture. Heat to boiling; reduce heat to medium-low. Cover and cook 8 to 10 minutes, stirring occasionally, until vegetables are crisp-tender.

Meanwhile, in medium saucepan, heat water, butter and garlic powder to boiling. Remove from heat; add milk. Stir in potato flakes and cheese. Add egg; blend well.

Spoon beef mixture into ungreased 8-inch square (2-quart) or oval (2 1/2-quart) glass baking dish. With large spoon, make 6 mounds of potato mixture on top of beef mixture to resemble ghosts. Place 2 reserved peas on each mound to resemble eyes. Bake 20 to 25 minutes or until potatoes are set and mixture is thoroughly heated.