Prep Pan: Grease a 10-cup dome-shaped cake pan with butter, dust lightly with flour, and preheat oven to 350°F (175°C).

Make Batter: Cream together unsalted butter and granulated sugar until light and fluffy. Add eggs one at a time, followed by vanilla extract. In another bowl, whisk flour, baking powder, and salt, then alternately mix into wet ingredients with milk until just combined.

Add Swirl: Pour half of the batter into prepared cake pan, dollop raspberry preserves over the surface, cover with remaining batter, and gently swirl with a knife.

Bake & Cool: Bake in preheated oven for 45-55 minutes or until a toothpick comes out clean. Cool in pan for 10 minutes before transferring to a wire rack.

Coat with Coconut: Brush the cooled cake with water or syrup to help the coconut adhere, then press shredded coconut onto the surface and dust with powdered sugar if desired.