Prepare all the ingredients. Place the grated cassava in a bowl of water to rinse, then transfer to a cloth bag and squeeze out as much water as possible.

In a bowl, whisk together the egg, salt, butter, vanilla, and tapioca starch until smooth. In another bowl, mix the cassava with sugar, condensed milk, and shredded coconut. Combine the egg mixture with the cassava mixture and mix until well blended. Finally, add the coconut milk, reserving 2 tablespoons to brush on top of the cake later.

Stir the pecans into the batter. Sprinkle a few extra pecans on top. Pour the batter into a baking pan. Preheat the oven to 340°F (170°C) and bake for the first 30 minutes. When the top of the cake is set, remove from the oven and brush the reserved coconut milk evenly over the surface.

Return the cake to the oven and bake for another 30 minutes. The cake is done when a toothpick inserted comes out dry. Let the cake cool completely before removing it from the pan.