Basic Cake Mix: 2 cups cake flour, 1 1/2 cups granulated sugar, 4 teaspoons baking powder, 1 teaspoon salt, 1/2 cup butter, cut into bits, 3 tablespoons vegetable oil.
For the Cake: 1/2 cup finely chopped walnuts, 1 (3 1/2 ounce) package vanilla instant pudding mix, 1/2 cup milk, 4 eggs, 1/2 cup whaler vanille rum (Hawaiian-style rum), 1/2 cup vegetable oil, 1 teaspoon vanilla extract, Rum soaking Glaze, 1/2 cup butter (do not substitute), 1/4 cup water, 1 cup granulated sugar, 1/2 cup whaler vanille rum (Hawaiian-style rum).
Basic Cake Mix: In a large mixing bowl, combine basic cake mix ingredients. On low speed combine ingredients until the mix is the consistency of fine gravel, and all particles are about the same size. This mix may be contained and stored for up to 3 months in the refrigerator.
For the Cake: Preheat oven to 325 degrees. Spray a large Bundt pan (12 cup) with nonstick cooking spray. Sprinkle the chopped walnuts on the bottom. Place Basic Cake Mix, pudding mix, milk, eggs, rum, oil, and vanilla extract in a large bowl and combine on medium speed with electric mixer for 2 to 3 minutes, scrape down the bowl halfway through. Batter should be very smooth. Pour into Bundt pan. Bake for about 55 minutes- until fully golden and tester comes out clean and cake springs back. Remove from oven and place on a cooling rack while making the soaking glaze.
Rum Soaking Glaze: Combine butter, water and sugar in a small saucepan. Bring to a boil carefully as mixture boils over very easily. Reduce to a simmer and cook until sugar is dissolved and syrup is well combined and a little thicker. Remove from the heat and add the rum, mix to combine. While cake is still cooling, pour some of the hot syrup on top of the cake, allowing it time to soak in (this may take a few minutes as there will be a lot of syrup) continue to add syrup until all of the syrup is added. Allow cake to cool completerly in pan before turning out onto serving platter. This cake is delicate, so once it is turned out, it can not be moved around easily. Can be eaten when fully cool, but even better the next day!