Preheat the oven to 350°F.
Grease and flour the inside of a 10-inch bundt pan.
Stir ½ cup of the milk together with the flaxseeds in a large mixing bowl. Set the mixture aside and let it sit for at least 5 minutes, to allow the seeds to gel.
While the flax mixture sits, whisk the flour, baking powder, and salt together in a separate large mixing bowl. Set this aside for now.
Add the sugar and brown sugar to the bowl containing the flax mixture, then use an electric mixer at high speed to beat the ingredients together for about 1 minute, until the mixture becomes frothy.
Turn the mixer speed down to low. While running the mixer, slowly drizzle in the remaining ½ cup of milk, followed by the vegetable oil, rum, vanilla extract, and almond extract.
Begin beating the flour mixture into the wet ingredients, adding about a third at a time, and beating in each portion completely before adding more.
Pour the batter into the prepared cake pan.
Bake the cake for 50 to 60 minutes, until a toothpick inserted into the cake comes out clean of batter.