01 -  Preheat the oven to 175°C. Line a muffin tin with cupcake liners. 
 02 -  In a large bowl, cream together the butter and sugar until light and fluffy. Add mashed bananas, eggs, and vanilla. Beat until well combined. 
 03 -  In a separate bowl, whisk together flour, baking powder, baking soda, and salt. 
 04 -  Add the dry ingredients to the wet mixture in two batches, alternating with the milk. Mix until just combined. 
 05 -  Divide batter evenly among cupcake liners, filling each about ¾ full. 
 06 -  Bake for 18-20 minutes, or until a toothpick inserted comes out clean. Let cool completely before frosting. 
 07 -  Beat softened butter until creamy. Gradually add powdered sugar, beating on low to combine. 
 08 -  Add cinnamon, vanilla, and a pinch of salt. Beat in cream, 1 tablespoon at a time, until desired consistency is reached. 
 09 -  Pipe or spread the buttercream onto cooled cupcakes.