• Preheat oven to 350°F and lightly grease or spray an 8 inch (or 9 inch) round cake pan. Adding parchment paper on the bottom helps, too.
• In a large mixing bowl, whisk together the sugar, baking soda, and salt. Sift in the flour and cocoa powder and whisk to combine all dry ingredients. Set aside.
• In a separate medium mixing bowl, combine oil, water, vanilla, and vinegar.
• Add the wet ingredients to the dry ingredients, stirring to combine. Whisk all briefly, only until smooth and no lumps remain. Texture and consistency should be like pudding.
• Pour cake mixture into prepared cake pan and bake for 25-30 minutes, or until cake springs back from touch and a toothpick inserted comes out clean.
• Remove cake from oven and let cool in the pan for 15 minutes. Remove it from the pan and let cool on a cooling rack for an additional 30 minutes.
• Frost with favorite topping or serve with powdered sugar and fresh fruit, if desired.

Storage and Leftovers:

• Cake will keep for 4 days covered at room-temperature. Powdered sugar will 'disappear' after a couple hours, so you may want to touch up before serving leftovers. Like many cakes, this one has more moisture on day 2.