Preheat oven to 350. Drain pineapple well, reserving syrup for glaze. Stir Bisquick,flour and baking soda together and set aside. Beat sugar,sour cream,butter, and vanilla together for 2 minutes. Add eggs and beat 1 additional minute. Add flour mixture and beat 1 minute longer. Mix in drained pineapple and rum. Pour into well greased 9 inch Bundt pan. Bake for about 45 minutes or until cake tests done. Remove from oven and spoon about half the glaze over cake. Let stand 10 minutes and then turn onto serving plate. Spoon on remaining glaze. Cool before cutting.
Glaze instructions: Combine sugar,butter and syrup. Stir over low heat until sugar is dissolved and butter is melted. Remove from heat and add rum, if desired.