Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x5-inch loaf pan.
Sift flour, sugar, cocoa, baking soda, and salt together in a large bowl. Add water, oil, vanilla, and vinegar; mix together until smooth and pour into the prepared pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 45 minutes.
You can use rice flour or something other than wheat.
Try adding chocolate chips or chopped nuts.