Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x5 inch loaf pan.
In a small bow, mix together butter and brown sugar until creamy. Stir in eggs and mashed bananas until well blended.
In a large bowl, combine flour, baking soda and salt. Add dry mixture to banana mixture until just combined.
Pour batter into prepared loaf pan.
For the topping: Combine the powdered sugar, flour, cinnamon, salt and melted butter. Using your hands, crumble the mixture. Spread over uncooked banana bread batter in the loaf pan.
Bake the loaf in preheated oven for about an hour, until a toothpick inserted into center of the loaf comes out clean. Let bread cool in pan for 10 minutes, then turn out onto a wire rack.
Recipe by CHIC AND SUGAR at https://www.chicandsugar.com/2015/01/banana-bread-cinnamon-crumb-topping/