Preheat the oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners.
In a mixing bowl, combine mashed bananas, softened butter, and granulated sugar. Mix until well combined.
Add eggs, one at a time, mixing well after each addition. Then, stir in vanilla extract.
In another bowl, whisk together flour, baking powder, baking soda, salt, and ground cinnamon.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix.
Spoon the batter into the prepared muffin tin, filling each cup about two-thirds full.
Bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean. Let cool in the pan for 5 minutes, then transfer the cupcakes to a cooling rack to cool completely.
For the frosting, beat the softened cream cheese and butter together in a mixing bowl until creamy. Gradually add powdered sugar, mixing until smooth.
Add vanilla extract, ground cinnamon, and milk as needed to reach your desired consistency. Mix until well combined.
Once the cupcakes are completely cooled, pipe or spread the cinnamon cream cheese frosting on top of each cupcake.