- Preheat oven to 325℉. Spray a 9×5” loaf pan with cooking spray and line with parchment so it extends over the 2 long sides of the pan.
- In a medium bowl toss ¼ cup of the flour with macadamia nuts, apricots, and ginger.
- In another medium bowl whisk to combine remaining 1¾ cups flour, baking powder, and salt.
- In a large bowl or a stand mixer with the paddle, beat butter and sugar until fluffy, about 5 minutes. Beat in vanilla, then beat in eggs 1 at a time just until combined. Gently mix in flour, then fold in fruit and nut mixture.
- Scrape batter into prepared pan, smoothing the top. Bake until a toothpick inserted in the center comes out clean, about 1 hour. Let cool in the pan for 20 minutes, then poke cake all over with a skewer. Very slowly pour rum all over cake and let sit 10 minutes before transferring cake to a rack to cool completely.
- If desired, cake may be wrapped in a rum-soaked piece of thin kitchen towel, sealed in a plastic bag, and kept refrigerated for up to 2 months before serving.
- In a medium bowl or a stand mixer with the paddle, beat butter until smooth. Beat in rum.
- To serve, spread top of cake with icing, then slice.