Step 1

Preheat oven to 350°F. Line three 4-inch or two 6" round pan with parchment rounds, and grease with non-stick baking spray.

Step 2

Mix together all dry ingredients (flour, sugar, baking powder, salt) with a whisk until fully combined.

Step 3

Pour the melted butter, oil, and egg into the dry ingredients and whisk until combined. The batter will be thick.

Step 4

Add the buttermilk and vanilla extract, and mix until just combined (the key is to mix until the ingredients are JUST incorporated, so that the batter isn't over mixed).

Step 5

If desired, add in gel food coloring. Mix the color in by hand using a rubber spatula, scraping the sides and bottom of the bowl part way through.

Step 6

Divide batter evenly between the prepared cake pans.

Step 7

Bake for 30-33 minutes, or until a toothpick comes out clean. Allow the pans to cool for 10 minutes, then run an offset spatula around perimeter of the pan to separate the cake from the pan.

Step 8

Place cake layers into the freezer for 20 minutes, to accelerate the cooling process. Once the layers are fully cooled, carefully flip the pans and remove the layers from the pans.

Step 9

Use a serrated knife to level the tops of the layers, and then frost as desired.

Step 10

While the cake layers bake and cool, make the vanilla buttercream frosting.

Step 11

Beat the butter on a medium speed for 30 seconds with a paddle attachment, until smooth.

Step 12

Mix in the vanilla extract or vanilla bean paste and salt on a low speed.

Step 13

Slowly add in the powdered sugar, 1 cup at a time. Alternate with small splashes of cream.

Step 14

Continue to mix on low speed for a few minutes, until the desired consistency is reached.

Step 15

If the frosting is too thick, add in additional cream (1 tsp at a time). If the frosting is too thin, add in more powdered sugar (quarter of a cup at a time).

Step 16

If you plan to color the buttercream, add in the gel food coloring once the frosting is fully made, and beat on low until it reaches the desired color

Step 17

Stack and frost cake layers on a small plate or cake stand using a dab of frosting to help stick the first cake layer to the board.

Step 18

Add an even layer of buttercream between each cake layer with a large offset spatula.

Step 19

Add a thin coat of frosting around the cake, fully cover the cake layers.

Step 20

Smooth using a bench scraper, then chill the cake in the fridge (20 minutes) or freezer (5 minutes) until the frosting is firm to the touch.

Step 21

Add a second, thicker layer of frosting to the cake, and smooth using a bench scraper. Then decorate as desired!