Preheat your oven to 350°F (175°C) and generously grease a 9-inch round baking pan with butter. Line the bottom with parchment paper to ensure the pudding doesn't stick. This will make slicing and serving much easier.

In a large mixing bowl, whisk together the all-purpose flour, dark brown sugar, ground nutmeg, cinnamon, ginger, and salt. Ensure there are no clumps of brown sugar remaining.

In a separate bowl, combine 1.5 cups of the coconut milk (reserving 1/2 cup for the topping later), melted butter, and vanilla extract. Add the finely grated sweet potatoes and grated coconut, stirring until well incorporated.

Pour the wet sweet potato mixture into the dry ingredients. Stir thoroughly until a thick, uniform batter forms, ensuring all the flour is fully hydrated and no dry pockets remain.

Pour the batter into the prepared baking pan, smoothing the top evenly with a silicone spatula. Bake in the preheated oven for 60 minutes, or until the edges start to pull away from the pan and the center is mostly set.

Remove the pan from the oven and carefully pour the reserved 1/2 cup of coconut milk evenly over the top of the pudding. Return it to the oven and bake for an additional 30 minutes until the top is golden and forms a soft, custard-like layer.

Allow the pudding to cool completely in the pan on a wire rack before slicing, as it needs time to set into its signature dense texture. Serve a generous slice warm or at room temperature, optionally topped with a scoop of vanilla ice cream.