-(ab. 7.5 ounces) FOR CAKE: Position rack in top third of oven; preheat to 350 deg. Butter two 23 cm-diameter cake pans with 4 cm-high sides. Line bottoms with waxed paper rounds. Butter and flour paper. Sift flour, baking powder and salt into medium bowl. Using electric mixer, beat butter in large bowl until fluffy. Gradually add sugar and beat 2 minutes. Add eggs 1 at a time, beating well after each addition. Beat in dark rum and vanila extract. Combine sour cream and baking soda in medium bowl. Add mashed bananas to sour cream mixture and stir until well blended. Add dry ingredients to butter mixture alternately w banana mixture, beginning & ending w dry ingredients, Stir in chopped Butterfinger bars. Divide batter between prepared pans. Bake until center of cake feels firm and tester inserted into center comes out clean, about 30 min. Cool in pans on rack 10 min. Run small knife around sides of cakes to loosen. Turn out cakes onto racks and cool. Peel off waxed paper (Can be prepared 1 day ahead. Wrap cakes tightly and store at room temperature.)