Mix all dry ingredients

Break the egg, add oil, buttermilk and very warm water

Butter a pan and dust some flour

Bake in a preheated oven for about 35 minutes at 180 degrees or less depending on your settings or until a toothpick comes out clean

For the butter cream frosting, whisk butter and icing sugar until the sweetness is okay for you. You can add some teaspoon cocoa powder to make a chocolate buttercream.
Frost the cake when it cools down and enjoy or refrigerate to keep fresh.