Step 1

Preheat the oven to 350°F / 175°C. Line three eight-inch pans or four seven-inch pans with parchment rounds, and grease with non-stick baking spray.

Step 2

Mix 3 cups all-purpose flour, 3 cups sugar, 2 1/2 tsp baking powder, and 1 tsp salt in a stand mixer with a paddle attachment or hand mixer until fully combined.

Step 3

Mix in 1 cup of room temperature, unsalted butter slowly into the dry ingredients on a low speed. Continue to mix until no large chunks of butter remain, and the mixture looks like moist sand.

Step 4

Pour in 1 cup of egg whites and mix on low until just incorporated. Mix in 1 1/2 cups of buttermilk in two installments, at a low speed.

Step 5

Add in 2 Tbsp of vegetable oil and 2 tsp of vanilla extract and mix at a low speed until fully incorporated. If you plan to color your cake layers, add in the gel food coloring with the oil and vanilla.

Step 6

Scrape down the sides of the bowl with a rubber spatula, then beat on a medium speed for about a minute to make sure everything is properly mixed. This also helps lighten the texture of the cake layers a bit.

Step 7

Divide the batter evenly between your prepared pans. I like to use a scale to make sure each pan has the same amount of batter and will bake up to the same height.

Step 8

Bake for 33-35 minutes or until a toothpick comes out with a few moist crumbs.

Step 9

Let the pans cool for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate the cake from the pan.

Step 10

Place the cake layers into the freezer for 30 minutes to accelerate the cooling process. Once the layers are fully cooled, carefully flip the pans and remove the layers.

Step 11

Use a serrated knife to level the tops of the layers right before you plan to assemble your cake, or you can wrap and freeze them if you're making them in advance.

Step 12

If you make these cake layers in advance and freeze them, let them thaw for about 20 minutes before making your cake. The cake layers should still be slightly cold to the touch, which will make it easier to assemble your cake.

Step 13

While the cake layers bake and cool, make the vanilla buttercream frosting. Beat 2 cups of butter on a medium speed for 30 seconds with a paddle attachment or hand mixer until smooth.

Step 14

Mix in 1 Tbsp of vanilla extract and 1/2 tsp salt on a low speed.

Step 15

Slowly mix in 7 cups of powdered sugar on a low speed. Add 1/4 cup of heavy cream halfway through to make the frosting easier to mix. Continue to mix on a low speed for a few minutes until the desired consistency is reached.

Step 16

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

Step 17

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

Step 18

The last component to make is the white chocolate ganache! Add 1/4 cup of heavy cream to a heat-proof bowl in the microwave for 45 seconds, until it's just beginning to bubble. If you don't have a microwave you can also heat the cream in a double boiler.

Step 19

Gently pour 1 cup of white chocolate chips into the heavy cream, making sure they are fully covered with cream. Let the mixture sit for 1 minute.

Step 20

Stir slowly until the cream and white chocolate are combined. If some bits of chocolate are not fully melted, heat the mixture again for 15 seconds, and stir. Repeat as necessary until all the chocolate bits are fully melted and incorporated.

Step 21

Then mix in the gel food coloring, if desired. Let the mixture cool until the desired viscosity is reached (barely warm to the touch). If it seems too thin or thick, you can add a touch more chocolate chips or heavy cream. The type of cream and white chocolate that you use can affect the consistency, so feel free to adjust as needed.

Step 22

Then it's finally time to assemble this drip cake! Stack and frost cake layers on a greaseproof cake board, using a dab of frosting to help stick the first cake layer to the board.

Step 23

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

Step 24

Once the layers are stacked, spread a thin coat of frosting around the cake, to fully cover the cake layers. Smooth using a bench scraper, then chill the cake in the fridge (30 minutes) or freezer (10 minutes) until the frosting is firm to the touch.

Step 25

Next, add a second, thicker layer of frosting to the cake and smooth using a bench scraper. If you're struggling to get smooth sides on your cake, I share all my tips and tricks in this smooth cake tutorial.

Step 26

Chill the cake again in the fridge (30 minutes) or freezer (10 minutes) until the frosting is firm to the touch. This step is crucial because it will prevent the ganache drips from melting the frosting and it keeps the drips from running too far down the cake.

Step 27

Add the drips to the cake using a plastic squirt bottle or spoon following the pictures and tips in the post above. Then decorate as desired!