1-Let’s get into the fun part making these cupcakes! Start by preheating your oven to 350°F (175°C) and lining a cupcake tray with paper liners. This sets the stage for a smooth baking process and helps everything come together just right.

2-First, whisk the cocoa powder and baking soda with boiling water for the chocolate batter. Stir in melted butter, vegetable oil, sugar, vanilla extract, salt, egg, egg yolk, heavy cream, and flour until combined, then spoon about 2 tablespoons into each of the 22 lined muffin cups.

3-Next, prepare the vanilla batter by sifting cake flour, baking powder, and salt, then mix with softened butter, sugar, vanilla bean seeds, egg whites, milk, and vanilla extract. Carefully add 2 tablespoons of this batter on top of the chocolate layer in each cup, making sure the layers stay separate.

4-Detailed Baking Steps
1. In a large bowl, cream together softened butter and granulated sugar until light and fluffy, ensuring a smooth batter base.
2. Add eggs one at a time, mixing thoroughly after each addition to incorporate air for a light texture.
3. Alternately mix in dry ingredients and milk, starting and ending with dry ingredients. Divide the batter evenly into three bowls.
4. Flavor each bowl add vanilla extract to one, cocoa powder to the second, and prepare the strawberry mix as needed.
5. Carefully layer each flavor into the cupcake liners to create distinct Neapolitan layers.
6. Bake for 16 to 19 minutes until a toothpick inserted comes out clean. Allow cupcakes to cool completely before frosting with the prepared strawberry buttercream.
7. For dietary variations, swap ingredients as needed in each step like vegan eggs, gluten-free flours, or sugar alternatives without changing the great taste.