In a large mixing bowl, add 1/4 cup granulated sugar, 1/2 cup golden brown sugar, and 3/4 cup of unsalted melted butter. Use an electric hand mixer to combine everything together for about 1 minute on medium-low speed.
Then add 1 teaspoon vanilla extract along with 2 large eggs and mix them in on medium speed.
Now in a separate bowl, mash up 4 ripe bananas (medium-sized). Then add them to the muffin batter.
Then sift the dry ingredients in this order: 1 3/4 cups all-purpose flour, 1 teaspoon baking soda, and 1/2 teaspoon salt. Now mix the dry ingredients into the banana muffin batter.