Sift all dry ingredients into large bowl so as to avoid clumps.
Add all wet ingredients and mix thoroughly.
Prepare 9-inch springform pan with parchment paper and pour in the batter evenly.
Bake for 45 minutes to an hour (an hour for pretty fudgey, 45 minutes for ultra fudgey).
In the meantime prepare your icing by grinding all ingredients in the food processor until very smooth. This might take a few minutes. If your food processor isn't very strong, you might want to soak your cashews in water for a couple hours first (and then discard the water before using).
Let cake cool for at least 20 minutes before removing from pan, and let cool nearly completely before icing.