Preheat oven to 350°F. Line a muffin tin with 8 liners.
In a large bowl or stand mixer, cream butter and sugar until fluffy. Mix in egg and vanilla just until dispersed. Add salt, baking soda, baking powder and flour. Mix until combined, followed by mashed banana. Mix until smooth.
Divide batter among liners, using 1 large cookie scoop each or roughly 2/3 full. Bake for 15-18 minutes or until a cake tester inserted comes out clean or with only a few moist crumbs. Cool in pan for 5 minutes prior to transferring to a wire rack to cool completely.
Prepare frosting in a large bowl or stand mixer. Beat butter until smooth. Mix in cocoa, followed by powdered sugar and vanilla. Gradually add in 1 tablespoon of heavy cream at a time until desired consistency is reached.
Nutritional information is provided as a courtesy and is an estimate only. Nutrition information can vary for a variety of reasons. For the most accurate data, use your preferred nutrition calculator with the actual ingredients you used to make this recipe.
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