Rum Cake from Scratch

Rum Cake from Scratch
Adapted by Always Order Dessert to be completely homemade from a recipe found on Food.com 

Ingredients

for the cake: 
1/2 cups walnuts, crushed
1 1/2 cups granulated white sugar
1 stick (1/2 cup) butter, softened
3 tablespoons + 1/2 cup grapeseed or canola oil, separated
1 3/4 cup all purpose flour
1/4 cup cornstarch
4 teaspoons baking powder
1 teaspoon kosher salt
1 cup DIY vanilla instant pudding mix
(click for my easy homemade pudding mix recipe!; you can also use packaged pudding mix)
3/4 cup whole milk
4 large eggs
3/4 cup dark rum (recommended: Tortuga Rum)
1 tablespoon pure vanilla extract

for the rum syrup:
1 stick (1/2 cup) butter
1/2 cup water
3/4 cup granulated white sugar
1 teaspoon Kosher salt
1/2 cup dark rum

Special Equipment: One 10-15 cup Bundt pan

Preheat oven to 325 degrees. Grease and flour bundt pan, and drop crushed walnuts into the bottom of the pan. Set aside.

In the base of a mixer, cream the 1 1/2 cups granulated sugar and the 1/2 cup butter. Add the 3 tablespoons oil, flour, cornstarch, baking powder, and kosher salt combining until evenly distributed. (Mixture will look like fine crumbs.) Mix in the pudding mix.

In a separate bowl, whisk together the eggs, milk, rum, vanilla extract, and remaining vegetable oil. Add to the dry mixture and mix well until combined. The batter will be smooth, thin, and pour easily.

Pour into the prepared bundt pan and bake for 50 to 60 minutes, or until a tester inserted in the cake comes up clean.

Let cool in pan for 10 minutes, then invert onto a rack. Let cool for 20 to 30 minutes.

While the cake cools, prepare the rum syrup: In a large saucepan with high sides, combine the butter, water, granulated sugar, and salt. Cook over medium heat until the butter completely melts and the sugar dissolves. Let reduce slightly, keeping an eye on it so it doesn’t boil over. Remove from the heat and stir in the rum (it will bubble).

Wash and dry the bundt pan, then place over the cool cake and invert the cake back into the pan. Pour the hot rum syrup all over the cake and let soak for 8 hours (overnight). In morning, invert the cake back onto a serving platter. Keeps covered for 1 week at room temperature.