Preheat oven to 350F. Beat butter at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add eggs, one at a time, beating after each addition. Stir in mashed bananas, rum and vanilla. Combine 1-1/2 cups flour and next 4 ingredients. Add to butter mixture, mixing until well blended. Pour into a greased and floured 10 inch tube pan; set aside.
Combine 1/2 cup flour, pecans, brown sugar, and butter; sprinkle over batter. Bake at 350F for 55 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on wire rack for 10 15 minutes; remove from pan, and let cool completely on wire rack.
Cajun Country -- New Iberia, Louisiana