Step 1

Preheat the oven to 350F and grease the inside of two 8” round cake pans, then line the bottoms with parchment paper. If you have them, wrap the pans in damp cake strips as this will give you the most even bake.

Step 2

In a large bowl using a hand or stand mixer with the paddle attachment (a stand mixer makes this recipe easier), mix together the cake flour, sugar, milk powder, baking powder, baking soda, and salt.

Step 3

With the mixer running on medium-low speed, drop in slices of the butter one at a time to slowly incorporate into the dry ingredients.

Step 4

Once all the butter is added and it has started to break down into small lumps (about 2 minutes), slowly pour in the oil with the mixer still running. Continue to mix for another minute or just until the mixture appears to have a very fine and crumbly texture.

Step 5

Now in a two cup measuring glass, mix together the water, sour cream, vinegar, and vanilla. Pour into the batter and mix on medium-low speed until smooth and combined, about 1 minute.

Step 6

Crack the eggs into that same 2 cup measuring glass and beat with a fork. With the mixer running on medium-low speed, slowly pour in the eggs. Once all the eggs are added, continue mixing until you reach a very smooth and creamy batter – but careful not to over mix.

Step 7

Remove the bowl from the mixer and use a rubber spatula to scrape down the sides and bottom to make sure everything is evenly combined. This will create a pourable batter that isn’t too thin or too thick.

Step 8

Divide the batter between the two pans and spread even. Bake the cakes on the middle rack for 35-40 minutes or until the tops are golden and a toothpick inserted comes out clean with a few moist crumbs.

Step 9

Allow the cakes to cool in the pan for about 20 minutes, then turn them out onto a cooling rack to cool completely before making the frosting.

Step 10

Using a hand or stand mixer with the whisk attachment (a stand mixer makes this recipe easier), mix the butter on medium-high speed for 5 minutes. Then scrape down the bowl and mix again for another 5 minutes until the butter is glossy and white.

Step 11

Now add in the powdered sugar, salt, and vanilla and mix on medium-low speed just to incorporate, then increase to medium speed until smooth and combined. Last, mix in the water to create a creamy frosting.

Step 12

To assemble, slice off the tops of the cooled cakes to create level surfaces. Lay one cake face up and spread a good heaping cup of frosting on top in an even layer.

Step 13

Lay the other cake face down on top of the buttercream layer and cover the entire cake with the remaining frosting. If you think your buttercream became a little TOO soft and your cake is having trouble staying in place, pop the cake in the refrigerator for about 30 minutes before continuing.

Step 14

Once frosted, it’s ready to slice and serve! It’s best at room temperature, but it’s also really good chilled. Store the cake in a container in the refrigerator and it will keep nice and moist for about 3 days. Enjoy!