Grease a dome-shaped cake pan with butter and dust lightly with flour. Preheat oven to 350°F (175°C).

Cream softened unsalted butter and granulated sugar for about three minutes until light and fluffy. Add eggs one at a time, then stir in vanilla extract.

In a separate bowl, whisk together flour, baking powder, and salt. Gradually add to the wet mixture, alternating with whole milk.

Pour half of the batter into the prepared pan, dollop raspberry preserves on top, then spoon the remaining batter and swirl.

Bake for 45 to 55 minutes, or until a toothpick comes out clean. Cool for 10 minutes before transferring to a wire rack.

Once cooled, brush the surface lightly with water or simple syrup and press sweetened shredded coconut onto the cake. Dust with powdered sugar before serving.