• Preheat the oven to 350 °F. Generously butter and flour a 12 cup Bundt pan or using baking spray.

Make the batter

• Whisk together 2 large eggs, 2 large yolks, 2 teaspoons vanilla extract and 1/2 cup of the buttermilk, set aside.
• Sift 11 ¼ oz cake flour, 11 oz granulated sugar, 1 tablespoon baking powder and ½ teaspoon table salt into a mixer bowl. Mix on low speed to combine the dry ingredients. Toss 6 oz unsalted butter into the flour mixture.
• Add the reserved 1/2 cup of buttermilk increase the speed to medium. Mix on medium high for 2 minutes to aerate the batter. Scrape the bowl.
• Add the eggs in 3 batches, scraping the bowl between each addition. Pour the batter into the prepared pan.
• Bake until the cake springs back when lightly pressed or a toothpick inserted into the center comes out clean, about 45 minutes.
• Cool for 5 minutes in the pan. Invert the cake onto a cooling rack set over a clean sheet pan.

Make the Glaze

• Combine 8 oz confectioner sugar, 1 teaspoon vanilla and 2 oz buttermilk and whisk until smooth.
• Pour the glaze over the still slightly warm cake. You can scoop up the glaze from the sheet pan and use it to fill in any gaps in the glaze.
• Cool completely and allow the glaze to set. Transfer to a serving plate.