- Preheat the oven to 325 degrees F. Grease and flour three 8 inch pans. We like to line the bottom of our pans with circles of parchment paper. 
- In a medium bowl, whisk the cake flour, baking powder, baking soda, and salt for 30 seconds and set aside. 
- In another bowl, combine the buttermilk, vegetable oil, and vanilla extract. Set aside. 
- In the bowl of your mixer, add the softened butter and softened mascarpone cheese and mix at medium speed until smooth. 
- Gradually add the sugar and mix at medium speed for 3 minutes. 
- Add the room temperature eggs one at a time, mixing after each until the yellow of the yolk has blended. 
- With the mixer on low speed, alternately add the flour mixture and the buttermilk mixture, beginning and ending with the flour mixture (We did 3 additions of the dry mixture, 2 additions of wet). After the last addition, mix just until well combined. 
- Divide the batter between the three prepared cake pans. 
- Bake at 325 degrees F for 28-30 minutes or until a toothpick inserted into the center comes out clean or with just a few crumbs attached. Let cool for 5-10 minutes in the pans on a wire rack before turning out. 
- This recipe makes approximately 8 cups of batter. Works for cupcakes also (although there will be little to no dome).