Follow these easy-to-follow steps to create your Neapolitan Cake:

Preparing Cake Layers

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and grease three 8-inch round baking pans.
2. Prepare Chocolate Layer: In a bowl, whisk together flour, cocoa powder, baking powder, and salt. In another bowl, beat butter and sugar until creamy. Mix in eggs and vanilla, then gradually add the dry ingredients and milk. Mix until smooth. Pour the batter into one prepared pan.
3. Prepare Vanilla Layer: In a bowl, whisk flour, baking powder, and salt. Cream the butter and sugar in another bowl. Beat in eggs and vanilla, then alternate adding dry ingredients and milk. Mix until smooth. Pour this batter into the second pan.
4. Prepare Strawberry Layer: Repeat the same steps as for the vanilla layer, but add the strawberry puree at the end to combine. Pour this into the third pan.
5. Bake: Bake each layer for 30-40 minutes or until a toothpick inserted in the center comes out clean. Rotate the pans halfway through baking.
6. Cool: Remove from the oven and allow the layers to cool in their pans for about 10 minutes. Carefully transfer them to wire racks and cool completely.

Assembling the Cake

7. Prepare Frosting: In a bowl, beat butter until creamy. Gradually add powdered sugar, milk, vanilla extract, and salt. Beat until fluffy. Optionally, add food coloring to different portions for a more colorful effect.
8. Layering: Place the chocolate layer on a serving plate. Spread a layer of frosting on top. Add the vanilla layer, more frosting, and then the strawberry layer.
9. Frosting the Cake: Spread frosting around and on top of the entire cake, smoothing it out for a professional look.
10. Decorate: Use any remaining frosting leftovers to add swirls or patterns. You may also add fresh strawberries or chocolate shavings on top for garnishment.