Step 1

Preheat oven to 350 degrees F. Grease 6 mini Bundt pans with baking spray.

Step 2

In a medium bowl, whisk together 1½ cups of flour, baking powder, and salt. In a small bowl, whisk the buttermilk with the rum if using.

Step 3

In the bowl of an electric mixer, beat together the sugar, oil, and butter on medium-high speed until fluffy, about 5 minutes. Add in the lime zest and beat for an additional minute. Scrap down the sides of the bowl as needed. Add in the eggs, one at a time, and beating until combined. Beat in vanilla extract.

Step 4

Add in a third of the flour mixture and half of the buttermilk. Mix until just combined. Then add another third of the flour and the rest of the buttermilk. Mix again until just combined. Scrape down the side of the bowl as needed. Add the rest of the flour and mix for 30 seconds. Finish incorporating the flour into the batter by hand with a rubber spatula to avoid over mixing.

Step 5

In a small bowl, toss the pineapples with the remaining two tablespoons of flour. Fold in the pineapples into the batter gently.

Step 6

Divide the batter into the prepared bundt pans, filling each about 2/Smooth the tops of each.

Step 7

Bake until cakes are golden brown and a toothpick inserted into the center comes out clean, about 20-25 minutes.

Step 8

Transfer to a cooling rack and allow the cake to cool in pan for 30 minutes. Using a small sharp knife, run it around the edge of the pan to loosen the cake and then invert the cake onto a cooling rack (lined with parchment paper) to cool completely.

Step 9

Whisk together all the ingredients in a small bowl. If the glaze is too thick, whisk in rum or lime juice, a teaspoon at a time.

Step 10

Just before serving, pour the glaze over the cake and allowing it to drip down the sides. Let glaze set for 20 minutes. Enjoy!