Stuffed Tomatoes with Spinach

I have make this quite often and everybody loves it so thought I would post it here.

STUFFED TOMATOES with SPINACH

½ cup onion
4 medium tomatoes
10 oz fresh spinach
6 slices bacon (fried and crumbled)
½ cup sour cream
a few dashes of Tabasco sauce and salt
1 cup mozzarella cheese (I use Mexican 4 cheese)
Shredded cheese.

Leave the stem end on the tomato, cut the other end off and hollow out the tomato. I start with a grapefruit knife then a spoon. It aint easy.
Cook onion in bacon drippings. Stir in spinach. Cover and cook for 4 minutes. Remove from heat and stir in sour cream. Add remaining ingredients. Bake at 375 degrees for 20 minutes. Sprinkle with mozzarella cheese and bake until melted.