Step 1: Preheat the Oven

Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans to prevent sticking.

Step 2: Prepare the Dry Ingredients

In a large bowl, combine the all-purpose flour, cocoa powder, baking soda, and salt. Whisk together to ensure even distribution of ingredients. Set the mixture aside.

Step 3: Cream the Butter and Sugar

In another bowl, cream the softened butter and sugar together until the mixture is light and fluffy. This process incorporates air into the mixture for a lighter cake texture.

Step 4: Incorporate Eggs and Vanilla

Add the eggs to the butter-sugar mixture one at a time, beating well after each addition. Stir in the vanilla extract until fully combined.

Step 5: Combine Dry and Wet Ingredients

Gradually mix the dry ingredients into the wet mixture, alternating with the buttermilk. Mix until well combined and smooth. Lastly, add the purple beet juice and stir until the batter is a consistent vibrant purple color.

Step 6: Divide and Bake the Cake

Divide the batter evenly between the two prepared cake pans. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

Step 7: Cool the Cakes

Once baking is complete, let the cakes cool in the pans for about 10 minutes. Then, carefully invert the cakes onto wire racks to cool completely.

Step 8: Prepare the White Chocolate Frosting

In a medium bowl, beat the softened butter until creamy. Gradually add the powdered sugar, beating after each addition until smooth.

Step 9: Blend in White Chocolate and Vanilla

Slowly incorporate the melted and cooled white chocolate along with the vanilla extract into the butter mixture. Adjust the frosting consistency by adding milk, one tablespoon at a time, until it reaches your desired thickness.

Step 10: Assemble the Cake

Once the cakes are completely cooled, spread a layer of frosting between the two layers. Use the remaining frosting to cover the top and sides of the cake evenly.