Cut tomato in 6 slices; halve each slice.
Stand tomatoes around edge of lightly greased 10-inch pie plate.
Combine hash and onion; spoon into pie plate.
Bake in 375°F oven 10 minutes.
Remove from oven.
Make 6 equally spaced depressions in hash; break an egg into each depression.
Lower heat to 325°F.; bake about 25 minutes, or until eggs are cooked to desired doneness