Preheat the oven to 325°F / 165°C and generously grease a 10-12 cup Bundt pan. Have all the ingredients at room temperature.
Beat 1½ cups of softened unsalted butter on high speed for about 2 minutes, until smooth and creamy. Add 225g of full-fat brick cream cheese and beat for about 1 minute, until completely smooth.
Beat in 2½ cups of granulated sugar, then ⅓ cup of sour cream and 2 teaspoons of vanilla extract. On low speed, add 6 large eggs one at a time, mixing each in fully.
Add 3 cups of cake flour, ½ teaspoon of baking powder, and ⅛ teaspoon of salt. Beat on medium speed just until combined, then spread in the pan.
Bake for 75-95 minutes, loosely tenting with aluminum foil halfway through, until a toothpick comes out clean.
Cool in the pan for 2 hours, then invert onto a wire rack to cool completely.
