Whisk together the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, and salt. Set aside.

Using an electric mixer on medium speed, beat the butter, brown sugar, and sugar until light and fluffy.

Add the eggs, one at a time, mixing well after each addition. Mix in the vanilla.

Reduce mixer speed to low. Add the flour in 3 portions, alternating with 2 portions of milk. Mix just until combined.

Transfer the batter to the prepared pan, and spread evenly.

Bake 50 to 60 minutes, or until a pick inserted into the center comes out clean.

Cool in the pan for 15 minutes. Then transfer the cake to a wire rack to cool completely.

Combine the brown sugar, sugar, butter, and cream in a medium saucepan. Cook over medium heat, stirring occasionally.

Bring to a boil and cook for 1 minute.

Remove the pan from the heat. Mix in the rum.

Add about 1/3 cup of confectioners' sugar and whisk to combine. Continue whisking while adding more sugar, a small amount at a time, until the mixture thickens. (I usually use close to 1 full cup of sugar to get the right consistency, but your results may vary.)

Pour the glaze over the cooled cake. Allow to cool and set. If you like, sprinkle with chopped nuts.