Preheat the oven to 350 F. Place the rack in the lower third of the oven. Spray the inside of a 10 cup bundt pan generously with Baker's Joy or some other grease/flour combo. Set aside.

Whisk together the flour, baking powder, baking soda, salt and ground pink and white peppercorns. Set aside.

Cream the butter using a stand or handheld mixer for about 1 minute, until broken down, and then add the seeds from the scraped out 3 vanilla beans along with the sugar. Cream until light and fluffy, about 5 minutes. Scrape down the sides and bottom of the bowl as needed. Add the eggs, one at a time, and beat each in. Then add the vanilla and beat it in. Reduce the speed to low and add the flour mix and buttermilk, in 3 and 2 additions respectively, alternating. Finish mixing by hand, making sure you scrape the bottom of the bowl.

Pour the batter into the prepared pan. Smooth the top. Bake for 45-50 minutes, until a cake tester inserted into the center of the cake comes out with only a few crumbs attached or dry, and the sides of the cake have started to pull away from the sides of the pan. Let cool in the pan for 10 minutes, and then invert onto parchment paper on a cooling rack (the parchment paper prevents the weight of the cake causing it to sink into the cooling rack holes). Let cool completely before glazing.

While the cake is cooling, prepare the glaze by whisking (or beating with handheld beaters) the ingredients together--add water to the desired consistency. Despite glazing the cake while it was cool, my glaze was still pretty transparent--perhaps I added too much water. In the end it did not matter as it was delicious.