In mixing bowl, lightly beat the water, vegetable oil, eggs, and brown sugar until combined, about 2 minutes. Stir in spice cake mix and flour, and mix until smooth. Stir in the vanilla, walnuts, raisins, tomatoes, and apple. Blend well.
Spoon the batter into a greased and floured 9x13 baking pan. Bake for 45 to 55 minutes, or until a wooden pick or cake tester inserted in the center comes out clean. Loosen the cake from the sides of the pan with a knife or spatula. Cool for 30 minutes.
Using a fine-mesh strainer or a sifter, sprinkle the top with powdered sugar. Optional: When serving, top each slice with a tablespoon of coconut and/or whipped cream, if desired.