Preheat oven to 350 degrees F. Lightly grease a muffin tin or use paper liners.

In a medium skillet melt the 2 tablespoons butter over medium heat. Add in 1 cup oats and stir to combine. Continue to stir for 2-3 minutes or until lightly brown and fragrant. Place oats in a food processor and grind into a flour.

In a large mixing bowl combine oat flour, flour, sugar, baking soda and salt. In a medium mixing bowl combine mashed bananas, buttermilk, melted butter, eggs and vanilla. Gently incorporate the wet with the dry mixing just until combined. Spoon into prepared muffin tin.

In a small bowl combine the topping ingredients and divide evenly over the muffins.

Bake for 20-25 minutes, or until toothpick inserted in middle comes out clean.