Preheat oven to 350°F. Grease an 8x8-inch baking dish well.
Melt butter and set aside.
Grate or process the cassava until fine. You should get about 2½ cups, loosely packed.
Grate the coconut until fine; about 1 cup.
In a medium bowl, mix cassava and coconut.
Add sugar, cinnamon, nutmeg, and black pepper.
Stir in melted butter, essence, and coconut milk until fully combined. The mixture should be loose and moist, but not watery.
Pour the mixture into a well-greased baking dish.
Bake for 1 hour to 1 hour 15 minutes, or until golden brown, the edges are caramelized and beginning to pull away from the pan, and a knife inserted in the center comes out mostly clean.
Allow to cool before slicing so the center has time to set.