Banana Crumb Cake Ingredients For the Crumbs: 5 TBSP unsalted butter, at room temperature ¼ cup sugar 1/3 cup packed brown sugar 1/3 cup all purpose flour ¼ tsp salt ½ cup chopped walnuts For the Bananas: 2 TBSP unsalted butter 1/2 cup brown sugar 2 TBSP banana liqueur 2 TBSP dark rum 2 large