Preheat the oven to 350ºF. Prepare the bundt cake by generously greasing the pan with unsalted butter.

In a stand mixer using the paddle attachment, cream the butter and sugar together on medium to high speed for 3 minutes. Be sure to scrape the bowl halfway through to prevent lumps forming at the bottom of the mixing bowl.

Add the egg yolks one at a time. Mix on medium to high speed for about 4 minutes, until all of the egg yolks have been fully incorporated.

Add the German Chocolate to the half cup of boiling water and stir until it is fully melted. Once cool, add the melted chocolate to the mixing bowl. Mix on medium speed for 3 minutes, until the chocolate is fully incorporated.

In a separate bowl, sift together the flour, salt, and baking soda. Add alternatively with the buttermilk to the chocolate mixture. Mix on medium to high speed for 5 minutes, scraping the bowl halfway through, until everything is completely combined.

In a separate mixing bowl, using the whisk attachment, beat the egg whites on high speed for 5 minutes, until stiff peaks begin to form. Gently fold the egg whites into the cake batter until fully combined.

Pour the batter into the prepared bundt pan and bake for 45 minutes until a tooth pick inserted comes out clean.

Remove the cake from the oven and let it cool for 10 minutes, before flipping the cake onto a wire rack or cake stand.

To make the ganache, heat the heavy cream in a saucepan over medium heat until it starts to simmer. Remove from the heat.

Pour the dark chocolate chips in with the hot heavy cream, place a lid on the saucepan, and let it sit for 3 minutes.

Gently stir until all of the chocolate has melted and combined with the cream.

Pour the ganache over the completely cooled bundt cake and drizzle with the cookie butter (optional).