Preheat your oven to 325°F (163°C).
Grease and flour a 10-cup Bundt pan thoroughly to ensure easy release of the cake.
In a large mixing bowl, combine the cake mix, instant pudding mix, eggs, water, and oil. Beat on medium speed until well combined.
Fold in the chopped nuts, if using, until evenly distributed throughout the batter.
Pour the batter into the prepared Bundt pan, smoothing the top with a spatula.
Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
While the cake is baking, prepare the rum sauce by combining butter, sugar, and rum in a saucepan. Cook over medium heat until the sugar has dissolved.
Once the cake is done, remove it from the oven and allow it to cool for about 10-15 minutes. Poke several holes in the top of the cake with a skewer.
Slowly pour the warm rum sauce over the cake, allowing it to soak in.
Let the cake cool completely in the pan for about an hour before inverting onto a serving plate.
Use a good quality dark or spiced rum for the best flavor in your cake and sauce.
Store the cake in an airtight container at room temperature for up to five days, or refrigerate to extend its freshness.
Consider serving the buttered rum cake with whipped cream or a scoop of vanilla ice cream for an extra indulgent treat.
Find it online: https://www.chyachya.com/buttered-rum-cake/