These buttermilk-oat muffins would be delicious with a cup of coffee, served at brunch, or made in advance for your weekday breakfast.
Preheat oven to 350 degrees.
In a mixing bowl, combine mix, buttermilk, eggs, 1/2 cup lightly packed light brown sugar, 1/4 cup softened butter, and bananas.
Fill greased muffin cups about 3/4 way full.
In a separate bowl, combine oats, remaining 1/4 cup brown sugar, and remaining butter. Mix with clean hands until you form a crumble.
Crumble mixture on top of muffins (about 1 tbsp. per muffin). Bake for 15-20 minutes, or until muffins are golden brown.