Heat oven to 350° F and lightly grease an 8-inch cake round with coconut oil. Line with a round of parchment paper.
In large bowl, sift together the dry ingredients. Add the coconut milk and water and stir well to combine.
Pour batter into pan, place in oven, and bake for about 40-45 minutes until a cake tester comes out clean. Remove from oven, place on a rack, and cool in pan 15 minutes. Turn out onto rack to cool completely.
Serve cake plain, with whipped cream, or ice cream. Cake will keep, well covered in the fridge, for 3 days.