Lightly butter a 1-1/2-quart casserole and set aside.
Toast bread and spread the 4 teaspoons of softened butter on one side of each slice. Reserve 1 slice of buttered toast for topping. Cut remaining toast into 1-inch pieces. Set aside.
In a medium skillet, cook the chopped celery, green pepper, onion, and garlic in the 2 tablespoons butter for about 5 minutes or until tender, but not brown. Set aside.
In a large mixing bowl, stir together undrained diced tomatoes, tomato paste, brown sugar, Italian seasoning, basil, thyme, oregano, and salt and pepper to taste.
Fold toast pieces and cooked vegetables into the tomato mixture. Turn the mixture into the prepared casserole. Place reserved toast slice on top.
Bake in a 350 degree F oven for 40 to 45 minutes or until the pudding is heated through. Serve warm.
If you like, omit the basil, thyme, and oregano and increase the Italian seasonings to 1-1/2 teaspoons.
To reduce the sodium in this dish, omit the salt and use low-sodium tomatoes.