1. Heat oven to 350 degrees F. Grease bottom of 13 x 9 x 2-inch cake pan. Dust lightly with flour; tap out the excess flour.
2. Prepare cake mix according to package directions, but decrease the water by 1/4 cup. Add the rum extract. Mix the batter according to the package directions. Stir in 1 cup of the cherry filling and 1/4 cup of the white chocolate, reserving the remaining cherry filling and white chocolate. Pour the batter into the prepared pan.
3. Bake in 350 degrees F oven 35 minutes or until wooden pick inserted in center comes out clean.
4. Cool the cake in the pan on a wire rack for 15 minutes. Invert the pan onto the rack; remove the pan. Invert the cake, right side up. Cool completely.
5. Place cake on serving tray. Frost top and sides. Sprinkle with remaining white chocolate. Top with remaining cherry filling.