Before you even begin the mixing process, it is extremely important that ALL of your ingredients are room temperature. I recommend taking your cream cheese, butter, eggs, and buttermilk out of the refrigerator 2 to 3 hours before you are ready to begin baking.
Once the ingredients have warmed up. Preheat the oven to 325 degrees F and prep a 10 or 12 cup bundt pan. I have found that the best way to grease a pan is by using the butter stick wrapper. This allows you to easily get all of the crevasses of the bundt pan. And it’s very important that the whole pan is covered for an easy release after baking.
Once the pan has been greased, flour it by adding a 1/4 cup of flour to the pan and then cover with plastic wrap and shake the pan so that the flour completely covers it. Discard any excess flour.
Prepare the batter, by creaming together the butter and cream cheese until completely smooth and no lumps remain. The best method for this is a stand mixer fitted with a paddle attachment, but a large bowl and a hand mixer will work too.
Add in the sugar in a slow continuous pour while beating the butter and cream cheese mixture. Continue to beat on medium speed for about 2 minutes after all of the sugar has been added. Scrape down the sides of the bowl as needed.
Mix in the buttermilk and vanilla. Then beat the eggs in one at a time just until the yolk had blended in. DO NOT overmix your eggs.
Add in the cake flour all at once and mix just until combined and smooth.
Pour the batter into the prepared baking pan and bake for approximately 80 minutes. Check around 1 hour for doneness, a cake tester should come clean from the center. If the bottom of the cake is looking too brown, loosely cover with aluminum foil for the last 20 minutes of baking.
Remove from the oven and allow to cool for at least 2 hours before inverting onto a cooling rack or cake stand and allowing to cool the rest of the way. Slice and serve with fresh berries, whipped cream, or a sauce of choice.