Heat oven to 350 degrees. Spray a 9x5-inch loaf pan with cooking spray.
In medium bowl, mix flour, baking powder, and 1/2 teaspoon salt; set aside. In large bowl, beat 1/2 cup butter and 1 cup brown sugar with electric mixer on medium speed until light and fluffy. Add eggs, one at a time, beating until just combined. Beat in vanilla and bananas until well blended. Gradually add flour mixture, beating at low speed. Pour batter into prepared pan.
Bake 45-55 minutes or until a toothpick comes out clean. Cool 20 minutes, run knife around edges to loosen loaf; remove from pan to cooling rack.
In small saucepan, heat 2 tablespoons butter and 1/4 cup brown sugar to boiling over medium heat, stirring constantly with whisk. Boil and stir 1 minute. Stir in whipping cream. Remove from heat, stir in powdered sugar and 1/4 teaspoon salt. Immediately drizzle over loaf. (glaze will harden quickly).