Marie's Tomato Pie

This Tomato Pie recipe came from a CSA member who discovered it 30 years ago and is still making it to this day.  Very decadent, she says!  Got to be good to hang onto it for that long, I say!  :)  

2 cups bisquick
1/2 cup water
tomatoes, sliced
1 cup grated cheddar cheese
Salt and pepper to taste
1 cup mayonaise

Mix bisquick and water in pie pan spread on bottom and sides.  Layer on top 5 to six sliced tomatoes.  Sprinkle cheese, salt and pepper over the tomatoes.  Spread mayo over top like meringue to seal.  Bake at 400 for 15 minutes then at 350 for 20 minutes more or until brown.