For the Cake:
1 cup chopped walnuts
1¾ cups all-purpose flour
¼ cup cornstarch
4 teaspoons baking powder
1 teaspoon kosher salt
½ cup unsalted butter, at room temperature
1½ cups granulated sugar
3 tablespoons + ½ cup canola oil, divided
1 cup DIY instant vanilla pudding mix (or one 3.4-ounce package of instant vanilla pudding)
¾ cup whole milk
¾ cup dark rum
1 tablespoon vanilla extract
For the Rum Syrup:
¾ cup unsalted butter
1½ cups granulated sugar
¼ cup water
Pinch of salt
½ cup dark rum
Preheat oven to 325 degrees F.
Grease and flour a standard Bundt pan (12-cup capacity). Sprinkle the chopped walnuts around the bottom; set aside.
Whisk together the flour, cornstarch, baking powder, and salt; in a medium mixing bowl and set aside.
Put your electric mixer on medium speed, cream together the butter and granulated sugar until light and fluffy, about 3 minutes. Add the flour mixture and the 3 tablespoons of canola oil, and mix on medium-low speed for a minute or two – the mixture should look like wet sand. Add the pudding mix and mix again on medium-low speed until combined.
Whisk together the eggs, milk, rum, remaining ½ cup canola oil, and vanilla extract in a medium mixing bowl. Add the egg mixture to the dry ingredients and beat on medium speed until thoroughly combined, about 2 to 3 minutes, scraping the sides of the bowl as needed. The batter is very thin so don’t panic. This is a good thing!
Pour the cake batter into the prepared Bundt pan and bake for 50 to 60 minutes, or until a tester inserted into the center of the cake comes out clean.
Towards the end of the baking time for the cake, you can start the rum syrup. Melt the butter in a medium-sized saucepan over medium heat. Once it is melted, add the sugar and the water. Boil for 5 minutes, stirring constantly. Turn off the heat and stir in the rum. Once it is mixed in, return it to medium heat for about 30 seconds.
As soon as the cake comes out of the oven, immediately pour about one-third of the rum syrup over the bottom of the cake. Pour slowly so it has time to seep into the cake. Let it sit for 5 minutes.
Invert the cake onto a serving platter. Using a fork or a skewer, poke holes all over the cake – the top, sides, and around the inside. Make plenty of holes. You want the rum syrup to seep into the cake! Slowly pour the remaining rum syrup over the top of the cake, allowing it to drip down the sides. You want to do this step very slowly. Very slowly. This will take you some time and do it this way so that the syrup actually seeps into the cake and doesn’t just pool on the bottom of the serving dish.
NOTE: If desired, make extra rum syrup and add it to your favorite glaze recipe and add a rum glaze to the top of the cake. The cake stands proudly on it’s own without the glaze but if you want to jazz up the presentation, this is just an idea for you.
Cool to room temperature before serving.