- Preheat the oven to 325°F and grease and flour two 8 or 9 inch cake pans. Set aside.
- In a large mixing bowl fitted with a whisk attachment, beat the softened butter and oil together until they become homogenous, about 3 minutes. This will not work if your butter is not completely room temperature.
- Slowly add the granulated sugar to the oil and butter, beating on high until the mixture is light and fluffy and turns a very pale yellow, about 3 minutes.
- Add the eggs in one at time, scraping down the bowl in between each addition. Add the vanilla extract. Beat the mixture on high for 3 minutes more to incorporate as much air as possible.
- In separate bowl sift together the cake flour, salt, and baking powder. Alternate mixing in the dry ingredients and the buttermilk in 4 batches, starting with the buttermilk and ending with the dry ingredients. It’s okay if the batter still has a few lumps in it–you don’t want to over mix it.
- Split the batter evenly into the prepared pans and bake for 30 minutes or until the cake is a lightly golden brown and springs back when pressed. This will depend on your oven. Take out of the oven and transfer to a cooling rack.
Source: https://bromabakery.com/how-to-make-the-best-vanilla-cake/