### Instructions:
1. **Prepare for Baking:** Preheat your oven to 325°F (160°C). Grease and flour a 10-cup Bundt pan or a 9×5 inch loaf pan.
2. **Combine Dry Ingredients:** In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
3. **Cream Butter and Cream Cheese:** In a large mixing bowl, using an electric mixer, cream together the softened butter and cream cheese on medium speed until light and fluffy, about 3-4 minutes.
4. **Add Sugar:** Gradually add the granulated sugar to the butter mixture, beating until well incorporated and the mixture is light and fluffy. Scrape down the sides of the bowl as needed.
5. **Incorporate Eggs:** Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
6. **Alternate Dry and Wet Ingredients:** With the mixer on low speed, alternately add the flour mixture in three additions and the milk in two additions, beginning and ending with the flour mixture. Mix just until combined, being careful not to overmix.
7. **Prepare Tropical Swirl:** In a small bowl, combine the pineapple preserves, mango puree, shredded coconut, lime juice, and lime zest. Mix well.
8. **Create the Swirl:** Pour about two-thirds of the pound cake batter into the prepared pan. Spoon dollops of the tropical swirl mixture over the batter. Top with the remaining pound cake batter. Use a butter knife or a skewer to gently swirl the tropical mixture into the batter, being careful not to overmix.
9. **Bake the Cake:** Bake for 60-70 minutes, or until a wooden skewer inserted into the center of the cake comes out with moist crumbs attached. The baking time may vary based on your oven and pan size.
10. **Cool and Glaze:** Let the cake cool in the pan for 15-20 minutes before inverting it onto a wire rack to cool completely.
11. **Prepare Glaze (Optional):** If using, whisk together the powdered sugar and milk/lime juice until smooth. Drizzle over the cooled cake.
### Short Tips:
* **Room Temperature Ingredients are Key:** This ensures a smooth, emulsified batter and a tender crumb.
* **Don’t Overmix:** Overmixing can lead to a tough cake. Mix until just combined.
* **Test for Doneness:** A skewer test ensures your cake is baked through without being dry.
* **Get Creative with Swirls:** Feel free to adjust the proportions of the tropical fruits or even add a different fruit puree for a unique twist.
* **Storage:** Store the cake at room temperature, covered, for up to 3 days, or in the refrigerator for up to a week.
