Preheat oven to 350 degrees.
Add gluten free flour, baking soda, baking powder, and cinnamon to bowl and gently stir together.
In large bowl mix butter, brown sugar, and 1/2 cup granulated sugar.
Add whole egg and egg yolk to butter and sugar mixture and combine well.
Slowly add flour mixture in small batches and mix until incorporated.
In separate bowl, peel bananas and mash with fork. Add vanilla extract.
Add banana mixture to batter and stir until just mixed, being careful not to over blend.
Line muffin tin, or grease well. Place 1 tablespoon batter in each cup.
Mix together remaining sugar and cinnamon. Sprinkle small amount over batter in muffin tins.
Place one more tablespoon batter in each cup.
Sprinkle more cinnamon sugar over each portion.
Using toothpick or small straw, gently mix together the sugar and batter in each tin.
Place in oven and bake for 25 minutes, or until toothpick inserted comes out clean.