01 -
Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish, then lightly dust it with flour.
02 -
In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.
03 -
Add the eggs one at a time, beating well after each addition. Then mix in the sour cream and vanilla extract.
04 -
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the butter mixture, mixing until just combined.
05 -
Gently fold in the mashed bananas.
06 -
Spread the batter evenly in the prepared baking dish and bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
07 -
Let the brownies cool completely in the dish on a wire rack.
08 -
To make the frosting, melt butter in a saucepan over medium heat, allowing it to brown slightly. Remove from heat immediately to prevent burning.
09 -
In a large bowl, mix the browned butter, powdered sugar, vanilla extract, and milk until smooth and creamy.
10 -
Once the brownies are cooled, spread the frosting over them evenly. Cut into squares and serve.