• Preheat your oven to 350°F (175°C) and grease your cake pans. Line the bottoms with parchment paper for easy removal.

Making the Cake Batter

• Step 1: Creaming the Butter and Sugar

  In a large mixing bowl, cream together the softened butter and sugar until light and fluffy. This process usually takes about 3-5 minutes with an electric mixer. Creaming incorporates air into the mixture, which helps create a lighter, more tender cake.
• Step 2: Adding Eggs and Vanilla

  Add the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed to ensure everything is well combined. Mix in the vanilla extract.
• Step 3: Combining Dry Ingredients

  In a separate bowl, whisk together the flour, baking powder, and salt. This step helps distribute the leavening agents evenly throughout the dry ingredients.
• Step 4: Alternating Wet and Dry Ingredients

  Gradually add the dry ingredients to the butter mixture, alternating with the milk. Begin and end with the dry ingredients, mixing on low speed just until combined. Be careful not to overmix, as this can lead to a tough cake.

Creating the Three Flavors

• Vanilla Layer

  Set aside one-third of the batter in a separate bowl. This will be your vanilla layer, so no additional flavoring is needed.
• Chocolate Layer

  In another bowl, combine one-third of the batter with the cocoa powder. Mix well until the cocoa is fully incorporated and the batter is a rich, chocolatey brown.
• Strawberry Layer

  For the final third of the batter, mix in the strawberry puree. If you want a more vibrant pink color, you can add a few drops of pink food coloring. Be careful not to add too much, as it can affect the flavor.

Baking the Cake

• Pour each flavored batter into a prepared cake pan, spreading it evenly. Tap the pans gently on the counter to remove any air bubbles.
• Bake the cakes for 25-30 minutes, or until a toothpick inserted into the center comes out clean. The baking time may vary slightly depending on your oven, so start checking at the 25-minute mark.
• Once baked, remove the cakes from the oven and let them cool in the pans for about 10 minutes. Then, carefully turn them out onto a wire cooling rack to cool completely.

Preparing the Neapolitan Frosting

• While the cakes are cooling, it's time to prepare the Neapolitan frosting. This tri-colored frosting will complement the cake layers perfectly.
• Step 1: Making the Base Frosting

  In a large mixing bowl, beat the softened butter until creamy. Gradually add the powdered sugar, alternating with the heavy cream. Mix in the vanilla extract. Beat until the frosting is smooth and fluffy.
• Step 2: Creating the Three Flavors

  Divide the frosting into three equal portions. Leave one portion as is for the vanilla frosting. Mix cocoa powder into the second portion for chocolate frosting. For the strawberry frosting, mix in the strawberry puree and a drop or two of pink food coloring if desired.

Assembling Your Neapolitan Cake

• Now comes the exciting part – putting your Neapolitan cake together!
• Step 1: Leveling the Cakes

  If your cake layers have domed tops, use a serrated knife to carefully level them. This will ensure your cake stacks evenly.
• Step 2: Stacking and Frosting

  Place the chocolate layer on your serving plate or cake board. Spread a layer of chocolate frosting on top. Next, add the vanilla layer and spread with vanilla frosting. Finally, top with the strawberry layer and spread strawberry frosting on top.
• Step 3: Frosting the Sides

  For a classic Neapolitan look, frost the sides of the cake with vertical stripes of chocolate, vanilla, and strawberry frosting. You can use a large offset spatula or a piping bag to apply the frosting.
• Step 4: Decorative Touches

  To finish your Neapolitan cake, you might want to add some decorative touches. Here are a few ideas:

  Pipe rosettes of each frosting flavor on top of the cakeGarnish with fresh strawberries, chocolate shavings, or vanilla beansCreate a chocolate drip effect on the top edge of the cakeUse a cake comb to create textured patterns in the frosting