Preheat oven to 350 F. Grease a 9 inch spring form pan with butter. Mix all the ingredients for the base in a large bowl, until the sugar is dissolved and everything is incorporated.
Spoon mixture onto greased pan. Make it level by pressing the surface with the back of the spoon. Bake at 350 for 1 hour or more, until the cake has set and there is no more liquid on top. Some brown spots might be present.
While the cake is baking, prepare the topping. In a bowl, combine flour and water and stir until smooth. Add the rest of the topping ingredients and mix well.
When the cake base is done, briefly remove it from the oven and pour the prepared topping gradually. Allow the liquid to be absorbed by the cake before pouring some more. Fill up to the brim, but with a little allowance so that the liquid does not spill. You might not need all the liquid depending on the height of your pan. Bake cake for another hour or until the top has set and the color is golden. Some areas will be darker than the others.
Let cake cool completely in the pan. Loosen sides with a knife and remove cake from pan.
Recipe adapted from Cassava Cake by Donovan Cooke from book World Class Cakes written by Roger Pizey.
You can also use frozen grated cassava sold in Asian groceries.