Preheat oven to 350° F. Spray each cupcake tin with baking spray.
In each cupcake tin, add a pat of butter to the bottom of each muffin tin. Bake in the preheated oven for a couple of minutes and remove when the butter is melted.
Add a 2 teaspoons of brown sugar to the bottom of each cupcake tin. If you like, add in a 1/2 teaspoon of rum. (optional)
Sprinkle with two teaspoons of chopped pecans.
Cut bananas diagonally into 1/8-inch-thick slices; place 3 to 4 slices over brown sugar mixture in each cupcake tin.
In a large bowl, beat together granulated sugar and remaining 1/4 cup butter at medium speed with an electric mixer until blended. Add eggs, one at a time, beating just until blended after each addition. Add milk, buttermilk, and vanilla; beat just until blended.
In a separate bowl, stir together the flour, baking powder and cinnamon.
Add the flour mixture into the bowl with the egg mixture and mix until blended.
Spoon the batter into each cupcake tin until each is about 2/3rd full.
Bake at 350° for 15 minutes or until a wooden pick inserted in center comes out clean.
As soon as these come out of the oven, invert the cupcake pan onto a lined cookie sheet, and leave the cupcake tin on top of the cupcakes for a minute or two. Lift the cupcake tin. If they stick, tap on the bottom of the tins, or run a butter knife around the edges to loosen.
Serve individually or with ice cream.