Line a 12-cup muffin tin with paper liners. Preheat oven to 350 degrees F.
In the bowl of a stand-mixer using the paddle attachment, or a large bowl using a hand-mixer, cream together on medium speed until light in color and fluffy the softened butter, sugar, and vanilla bean paste. Scrape sides of bowl with spatula.
Add in the eggs one at a time, making sure to incorporate each egg before adding the next.
Pour in buttermilk and mashed banana and mix until combined. Scrape down sides of bowl with spatula.
In a small bowl, mix together flour, baking soda, salt, and cinnamon. Add this mixture to the wet mixture and mix on medium speed for at least 1 minute.
Using a cookie scoop, distribute the cupcake batter between the 12 paper liners, they should be filled 2/3rds of the way up.
Bake for 18-25 minutes, or until tested with a toothpick and toothpick comes out of cupcake clean. When baked, remove from oven and set tin on cooling rack for 10 minutes, then remove cupcakes from tin and allow to completely cool on cooling rack.
In the bowl of a stand mixer using the paddle attachment or in a large bowl using a hand-mixer, cream softened butter and cream cheese on medium speed until smooth and creamy.
Add confectioners sugar, salt, and vanilla and begin mixing on LOW speed to get the sugar mixed in. Then mix on medium speed for a minute, scrape down sides of bowl, and then mix for another minute.
If frosting is too thick, add a teaspoon of milk or heavy cream. If frosting is too thin, add more confectioners sugar. You want the frosting to be thick enough to hold its shape, yet still creamy and spreadable.
Take a 12" disposable decorating piping bag, snip off the end with scissors, and insert a Wilton 2D tip into it.
Fill piping bag with a comfortable amount of Cream Cheese Frosting and pipe onto completely cooled cupcakes.
Immediately sprinkle the top of the cupcakes with your desired toppings: banana slices, mini chocolate chips, sprinkles or chocolate chunks and walnuts. Enjoy!