Peel and cut the sweet potato in small slices, for quicker cooking. Steam until tender.
Put the hot steaming sweet potato in a mixing bowl and immediately add the coconut oil and butter. Let both mix well into the sweet potato. Add the sugar and mix well. Add the maple syrup. Add the cacao powder. Mix well. Add the eggs and mix well.
In a second bowl, mix all of the dry ingredients you have not yet used.
Slowly incorporate the dry into the wet and mix well.
Use a spatula to transfer to a 9X9 pan, spreading out the thick mixture evenly. Bake at 200C (392F) for 10 minutes. Lower temperature to 180C (375F) and cook an additional 10 minutes. Let cool and then serve.