Preheat oven to 325°F (165°C). Grease and flour a bundt pan thoroughly, ensuring all crevices are coated.

In a large mixing bowl, cream together butter and sugar until light and fluffy, about 5 minutes using an electric mixer.

Add eggs one at a time, beating well after each addition. Mix in vanilla extract.

In a separate bowl, whisk together flour, baking powder, salt, cinnamon, and nutmeg.

Gradually add the dry ingredients to the butter mixture, alternating with milk, beginning and ending with flour mixture. Mix until just combined.

Fold in the grated coconut gently with a spatula until evenly distributed throughout the batter.

Pour batter into the prepared bundt pan and smooth the top with a spatula.

Bake for 50-55 minutes, or until a toothpick inserted into the center comes out clean and the top is golden brown.

While cake bakes, prepare the rum glaze: In a small saucepan, combine butter, sugar, and water. Bring to a boil, stirring constantly until sugar dissolves completely.

Remove glaze from heat and carefully stir in dark rum. Set aside to cool slightly.

When cake is done, remove from oven and let cool in pan for 10 minutes.

Using a skewer or toothpick, poke holes all over the cake while still in the pan.

Slowly pour half of the warm rum glaze over the cake, allowing it to soak in completely.

Let cake cool for another 15 minutes, then invert onto a serving plate.

Poke more holes in the top and sides of the cake, then pour remaining glaze over, letting it soak in.

Allow cake to cool completely before serving. For best flavor, wrap tightly and let sit for 24 hours before serving.