Preheat the oven to 325°F. Spray a 10-12 cup bundt pan with baking spray that has flour in it, or brush the pan with softened butter using a pastry brush and dust with flour.
In the bowl of a stand mixer, beat the butter and sugar on high speed for 2–3 minutes with the whisk or paddle attachment until creamy and smooth. Stop to scrape the bottom and sides of the bowl to ensure they are evenly mixed.
1 ½ cups (345g) salted butter, 2 cups (400g) granulated sugar
Add the sour cream, coconut extract, and vanilla extract. Mix again until light, fluffy, and pale, about another 1-2 minutes on high speed. Add the eggs, mixing just until combined. Scrape the bottom and sides of the bowl again.
1 cup sour cream, 2 teaspoons coconut extract, 1 teaspoon pure vanilla extract, 6 large eggs
Add flour, baking powder, salt, and shredded coconut. Mix on medium speed just until combined. The batter will be thick.
1 ¾ cups (354g) all-purpose flour, ½ teaspoon baking powder, ¼ teaspoon salt, 2 cups sweetened coconut
Spread the batter into the prepared pan and rap the pan against the counter a couple of times to remove any air bubbles.
Bake for 60 to 75 minutes in the preheated oven until a skewer comes out completely clean when inserted into the thickest part of the poundcake.
Loosely cover the pan with aluminum foil halfway through baking to prevent the top from browning too much.
Cool for 2 hours in the pan before turning out onto a wire rack to cool completely.
To make the glaze, whisk the powdered sugar, cream, and coconut extract in a medium bowl until smooth and a nice consistency that isn't too thin. Pour over the cooled cake, then sprinkle with the toasted (or untoasted) sweetened coconut flakes to decorate.
1 cup (120g) powdered sugar, 4-5 Tablespoons heavy cream, 1 teaspoon coconut extract, ¼ cup toasted sweetened coconut flakes