Preheat oven to 350.

Spray a cupcake pan with non-stick spray. Sprinkle 1/12th of the brown sugar into the bottom of each cup, then top with a pineapple ring.

Combine flour, baking powder, and salt in a small bowl. Add the butter and sugar to another bowl and beat until fluffy. Add the eggs, one at a time, mixing in between additions. Beat in the vanilla and rum.

Add half of the flour mixture and mix to combine. Mix in the milk and pineapple juice, then stir in the remaining flour. Gently fold in the poppy seeds.

Divide the batter among the cups of your pan, so that the pineapple ring is on the bottom. Bake for 18-22 minutes or until fully cooked.

Allow to cool, then invert pan onto a baking sheet to remove cakes.