Red and Green Casserole

I haven't met a vegetable I didn't like, from asparagus to zucchini and everyone in between. It is hard to choose a favorite. Of course, potatoes are a special category all by themselves.
For this recipe, let's look at the lowly green bean. It is easy to only consider 'em boiled with onions or combined with a cheese sauce. This recipe is a little different. Try it and see what you think.

Red & Green Casserole
3 slices raw bacon, chopped
1/2 cup chopped onion
16 ounce can French style green beans, drained
1/2 cup shredded sharp cheddar cheese
1/4 cup sour cream
1/4 cup mayonnaise
Salt and pepper to taste
1 fresh unpeeled tomato

Saute bacon in small skillet until barely crisp. Pour off all but 1 tablespoon drippings. Add chopped onions. Saute until onions are soft but not browned, about 2 minutes.
In medium mixing bowl combine green beans with rest of ingredients, except the tomato. Stir lightly to combine.
Place in buttered 1-1/2 quart casserole.
When ready to bake, cut tomato in half down through the stem end, then cut in quarters. Continue cutting in wedges until you have enough to cover green beans. Lay the tomato wedges on top of the casserole.
Just before serving time, bake at 350 F until heated through and bubbly around the edges, about 25 to 30 minutes.
The baking time depends on the temperature of the casserole at baking time. Serves 6.