1. Preheat the oven to 350°F
2. Line a baking sheet with parchment paper and set aside.
3. In the bowl of your stand mixer fitted with the paddle attachment beat the butter and sugar together for 2 minutes. Add in the egg, vanilla and bananas and mix for an additional minute, scraping the sides of the bowl as necessary. Mix in the baking soda and salt until incorporated.
4. Turn the mixer to low and slowly add in the flour, mixing until just combined.
5. Using a medium (2 tablespoon) cookie scoop, drop the dough on to the baking sheet 2 inches apart. Bake the cookies for 9-10 minutes or until the centers are set.
6. Transfer the cookies to a wire rack to cool completely.

For the Frosting

1. In a medium saucepan melt the butter, sugar, cream and together over medium-low heat. Bring the mixture to a full boil and boil for 2 minutes, stirring constantly.
2. Remove the pan from heat, stir in the salt, and allow to cool for 5 minutes. Whisk in the powdered sugar and then cool for an additional 15 minutes, whisking every so often.
3. Spread the frosting on the cookies.