Set your oven to 325°F (163°C). While it heats up, grab a bundt pan (10 or 12-cup size works). Grease it really well either with butter and a light dusting of flour, or use a baking spray that includes flour. Make sure to get in all the grooves so nothing sticks.

In a medium bowl, whisk together your flour, baking powder, baking soda, and salt. Set that aside for now.

In a large mixing bowl, beat the butter and sugar together on medium-high speed for about 3–4 minutes. You’re looking for a light and fluffy texture don’t rush this step, it makes a difference.

Crack in the eggs, one at a time. Beat well after each one so everything gets nice and incorporated. Once they’re all in, stir in the vanilla extract.

Now start combining the dry mix and the milk into the butter mixture. Do this in batches add some dry, then some milk, repeat starting and ending with the dry mix. Slowly pour in the rum and mix until the batter is smooth.

Pour the batter into your prepared bundt pan and smooth out the top. Pop it in the oven and bake for about 50–60 minutes. It’s ready when a toothpick inserted in the center comes out clean.

While the cake is baking, make the syrup. In a small saucepan, combine butter, water, and sugar over medium heat. Stir until the butter is melted and the sugar dissolves. Remove from heat, then stir in the rum and vanilla. Set it aside.

When the cake comes out of the oven, let it sit in the pan for 10–15 minutes. Poke small holes all over the top with a skewer or toothpick. Then, slowly pour the warm rum syrup over the cake (still in the pan), letting it soak in gradually.

Let the syrup absorb for another 10 minutes. Then carefully invert the cake onto a wire rack or serving plate. Let it cool completely before slicing and serving.