Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking pan and line with parchment paper.

In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.

In a larger bowl, cream together the unsalted butter and granulated sugar until light and fluffy.

Beat in the eggs one at a time, then add the vanilla extract.

Gradually add the dry ingredients to the creamed mixture, alternating with the buttermilk. Stir in the hot water until smooth.

Pour the batter into the prepared baking pan and bake for 25-30 minutes.

Whip together heavy cream, powdered sugar, and vanilla extract until soft peaks form.

In another bowl, tint shredded coconut with pink food coloring.

Once the cake has cooled, spread the whipped frosting over the top and sprinkle the colored coconut on top.

Refrigerate for at least one hour before cutting into squares and serving.