Preheat oven to 350 degrees and line 12 muffin cups with liners (foil is preferred)
Place butter into a small skillet over medium heat. Cook, let bubble and swirl pan until butter has turned golden brown. You’ll see brown bits form at the bottom of the pan. Transfer to a heat proof bowl and let cool for 5 minutes.
Pour butter into a large mixing bowl. Add sugar, bananas and vanilla mixing to combine. Add egg, stirring to combine. Stir in flour, baking soda and salt then stir in blueberries.
Fill prepared muffin cups 3/4 full and bake for 23-25 minutes, until baked through. Remove and let cool for 5 minutes if drizzling with icing. Muffins are great with or without icing.
To prepare icing, place powdered sugar and heavy cream into a medium bowl. Whisk until desired icing consistency. Drizzle over warm muffins if desired.