For the cake

1. Preheat the oven to 350°F. Lightly grease a 9×13-inch pan with cooking spray or shortening.
2. In a large mixing bowl, mash and measure the bananas then combine with the oil, eggs, and vanilla extract. Beat on medium speed until well incorporated. Scrape down the bowl as needed. Next mix beat in the sugars until well combined.
3. In a separate bowl combine the remaining dry ingredients and sift. Add half the dry ingredients, and half the buttermilk and beat on low speed just until the flour starts to incorporate. Add remaining ingredients (dry and liquid). Use a spatula to scrape down the sides of the bowl and stir the batter from the bottom to the top to ensure it’s well mixed.
4. Pour the batter into the prepared pan. Bake at 350°F for 20-25 minutes. Test the cake for doneness by inserting a toothpick into the center of the cake, it should be completely dry. Remove from the oven and allow to cool completely.

For the Frosting

1. Cut the butter into 1 tablespoon sized pieces and place in a saucepan. Turn the stovetop on to medium-low heat slowly bringing the butter to a boil, stirring occasionally. Once boiling, the bubbles will go from big to small, and once the milk solids start to turn golden brown, stir constantly until the golden color starts to darken. Immediately remove from the heat and pour into a heatproof bowl.
2. Refrigerate the browned butter for 20-30 minutes until it solidifies but it’s not too hard. This can also be placed in the freezer to speed up the process. Once chilled, stir the browned butter together with a spoon until the milk solids are mixed back into the butter.
3. Using the paddle attachment, whip the butter for 5-7 minutes, scraping down the bowl occasionally until the butter reached a whipped and fluffy consistency and it’s easily spreadable.
4. Next, cube the cream cheese and beat together with the butter until it’s well combined and free of lumps.
5. Add the powdered sugar, 1 cup at a time, mixing to combine before adding more and add in the vanilla extract, rum and salt together with the powdered sugar. Reserve the last ½ cup of powdered sugar, and only add if needed for a thicker consistency. Spread over cooled cake. Garnish with chopped pecan or walnuts if desired.