Preheat oven to 350 degrees F.
Mix first 5 dry ingredients in a greased 8″ square baking pan. Make 3 depressions in dry ingredients – two small, one larger. Pour vinegar in one depression, vanilla in the other and the vegetable oil in third larger depression. Pour water over all. Mix well until smooth.
Bake on middle rack of oven for 35 minutes. Check with toothpick to make sure it comes out clean. Cool. Top with frosting:
1 can (400 ml) full-fat coconut milk
1 bag dark, non-dairy chocolate chips (approx 285 grams)
Chill can of full-fat coconut milk overnight. When ready, flip can over and open with can opener. Pour off the water. Scoop only the solid white coconut cream into a pot. Add the chocolate chips into the pot as well and gently melt the coconut cream & chocolate chips together over low heat. Stir frequently and be careful not to burn.
Transfer this mixture into a bowl (cover with wrap) and then into the fridge for 2-3 hours (or overnight) until it firms up enough to whip into frosting. You really just have to eyeball it as the timing for individual batches will differ depending on how cold your fridge is.
When it’s firm, whip it with electric beaters until smooth and creamy. If it’s still too firm, you can leave it out on the counter for a bit longer.