FOR THE CAKE:
- 3 boxes white cake mix* (15.25 ounces each)
- 3 cups water
- 1 cup vegetable oil
- 9 large egg whites
- 1 cup sour cream
- 2 small boxes instant vanilla pudding mix (3.4 oz packages)
- purple food coloring
FOR THE FROSTING:
- 1 ½ cups salted butter room temperature
- 4 ½ cups powdered sugar
- 1 teaspoon vanilla bean paste
- ½ teaspoon salt
- 3-4 tablespoons heavy cream as needed
- purple sanding sugar if desired
MAKE THE CAKE:
- Preheat the oven to 350ºF. Line the bottom of four 9” round cake pans (that are at least 2″ deep)** with parchment paper. Spray with baking spray. If you don’t have parchment paper, grease the pans with CAKE RELEASE to ensure they come out cleanly.
- In a large mixing bowl, whisk together dry cake mix, water, oil, egg whites, sour cream and vanilla pudding mixes. Using a hand mixer works well to make sure this is all combined since it is a large amount of batter. Scrape the sides of the bowl as needed during mixing.
- Divide the cake into 4 separate bowls. Add 3 drops of purple food coloring to one bowl, 2 drops to another bowl and 1 drop to a third bowl. (Or use as much food coloring as you’d like, in decreasing amounts.) Leave one bowl of cake batter uncolored. Mix the food coloring into the cake batter until it is fully colored.
- Pour the cake batter evenly into the prepared cake pans. Place the pans into the oven to bake for 28-30 minutes or per the time indicated on the cake box. The top of the cake should spring back when you touch it.
- Once baked, remove the cakes from the oven and place them onto a cooling rack to cool completely.
MAKE THE FROSTING:
- A note about the frosting: For a naked cake with visible layers, make just one recipe of frosting. For a fully frosted cake, make 1 ½ -2 full recipes of the frosting.
- To make the frosting, cream the butter in the bowl of a stand mixer using the paddle attachment for 2-3 minutes or until it is well creamed and almost white in appearance.
- Add the remaining ingredients. Beat together on high speed for 2-3 minutes or until a smooth and fluffy frosting has formed. If the buttercream is too thick, add heavy cream a tablespoon at a time until you get the consistency you’d like.
- To frost the cake, place the darkest purple cake layer onto a cake stand or serving plate. If you so desire, slice the domed tops off of the cake layers for a more even final cake. Spread ⅓ cup of frosting over the surface of the cake. Place the medium colored layer of cake onto the bottom layer, ensuring that the cakes line up and that the top layer does not hang off of the bottom layer. Spread about ⅓ cup of frosting over the surface of the cake layer. Place the last colored layer of cake onto the frosted cake. Frost with ⅓ cup of frosting.
- Finally, place the yellow or white layer onto the cake. Frost the top and sides of the cake with the remaining frosting. For added effect, press purple sanding sugar onto the bottom and partially up the sides of the cake.
- If you would like to add little frosting swirls to the top of the cake, add a dot of purple food coloring about ½ cup of frosting. Spoon the frosting into a piping bag fitted with a tip of your choice (I like Wilton 1M or 2D). Pipe the frosting swirls onto the top of the cake after it is frosted.
- Store in an airtight container at room temperature for up to 2 days. Refrigerate or freeze any leftovers.
*I used Duncan Hines. **This makes a lot of batter for a tall cake. Make sure that your cake pans are at least 2″ deep so the batter doesn’t overflow.Refer to the article above for more tips and tricks.The calories shown are based on the cake being cut into 9 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**
Calories: 740kcal | Carbohydrates: 121g | Protein: 7g | Fat: 26g | Saturated Fat: 16g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 7g | Trans Fat: 1g | Cholesterol: 61mg | Sodium: 1006mg | Potassium: 126mg | Fiber: 1g | Sugar: 80g | Vitamin A: 707IU | Vitamin C: 1mg | Calcium: 254mg | Iron: 2mg