Recipe courtesy of Andrea K.

3/4 cup Andrea’s Gluten Free Flour Blend
1 1/3 cups certified gluten-free oats
1/4 teaspoon salt
1 teaspoon baking soda
1/2 cup butter or margarine, softened
2/3 cup packed brown sugar
2 eggs
1 cup mashed bananas
1 teaspoon vanilla extract

Stir together flour, oats, salt, and baking soda. 
In a large bowl, cream butter or margarine with brown sugar. 
Beat in the eggs, then the bananas and vanilla. 
Beat the flour mixture into the banana mixture. 
Turn the batter into a greased 8 inch square pan. 

Crumb Topping:
3/4 cup certified gluten-free oats
1/3 cup packed brown sugar
2 tablespoons butter or margarine, melted
1/2 teaspoon ground cinnamon

Mix oats, brown sugar, melted butter or margarine, and cinnamon together until crumbly. 
Sprinkle evenly over the top of the batter. 
Bake in preheated oven at 350 degrees F (175 degrees C) for 40 to 45 minutes, or until it tests done.