Preheat the oven to 350 degrees F (175 degrees C).
Melt brown sugar, butter, and honey for topping in a small saucepan over medium heat, stirring until smooth.
Pour butter mixture into the bottoms of two ungreased 8-inch round cake pans. Drain pineapple slices and reserve 1/4 cup juice for the cake. Layer pineapple slices on top of the butter mixture.
Combine buttermilk, rum, and reserved pineapple juice in a small bowl. Combine flour, baking powder, cinnamon, pumpkin pie spice, and salt in another small bowl.
Beat white and brown sugars with butter in a large bowl until creamy. Add eggs, one at a time, mixing well after each addition. Beat in vanilla. Mix in 1/2 of the flour mixture, then all of the buttermilk mixture, and finally the remaining flour mixture until well combined. Divide cake batter evenly between the two pans.
Bake in the preheated oven until cakes are golden and a toothpick inserted in the centers comes out clean, 30 to 35 minutes.
Remove from the oven place on wire racks until completely cooled, 30 to 45 minutes. Turn one cake out onto a serving plate, then carefully turn second cake directly on top of the first.