Preheat the Oven. Position a rack in the center of your oven and preheat to 350°F (175°C). Grease a 12-cup bundt pan with nonstick baking spray and dust with flour to prevent sticking.
In a medium bowl, whisk together the flour, baking powder, and salt.
In a separate bowl, whisk together the sour cream, coconut extract, and vanilla extract.
In a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed for 3-4 minutes until light and fluffy.
Reduce speed to low and add eggs one at a time, beating well after each addition.
With the mixer on low, add the dry ingredients in three parts, alternating with the wet ingredients, beginning and ending with the dry mixture.
Fold in the chopped white chocolate, ensuring even distribution.
Pour the batter into the prepared bundt pan and sprinkle 1/2 cup of shredded coconut over the top.
Place the bundt pan on a baking sheet and bake for 65-75 minutes, covering loosely with foil halfway through baking to prevent over-browning. The cake is done when a skewer inserted into the center comes out with a few crumbs attached.
Let the cake cool in the pan for 10 minutes. Place a serving plate or wire rack over the bundt pan and flip it over to release the cake.Let it cool completely before frosting. If you prefer toasted coconut, spread the shredded coconut on a parchment-lined baking sheet. Bake at 325°F (163°C) for 3-4 minutes until lightly golden and fragrant.Transfer immediately to a plate to prevent further toasting.
In a stand mixer, beat the cream cheese, butter, coconut extract, and vanilla extract on medium-high speed for 5 minutes until soft and creamy. Scrape down the bowl, then add confectioners' sugar and salt. Beat on low until combined, then increase to medium-high and beat for another 5 minutes until smooth.
Use an offset spatula to spread the frosting over the top of the bundt cake. Press the shredded coconut into the frosting, using a cookie sheet underneath to catch any excess.
Serve at room temperature. Store covered at room temperature for up to 3 days. To prevent drying, press plastic wrap against any cut edges.