Make the Cake:

1. Preheat the oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper and lightly grease it.
2. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
3. In a large mixing bowl, beat butter and sugar until light and fluffy (about 2 minutes).
4. Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.
5. Alternate adding the flour mixture and milk, beginning and ending with the flour. Mix until just combined.
6. Pour the batter into the prepared pan and spread evenly.
7. Bake for 18-22 minutes or until a toothpick inserted into the center comes out clean.
8. Let the cake cool completely before cutting.

Prepare the Filling:

1. Beat butter until creamy, then gradually add powdered sugar.
2. Mix in marshmallow creme and vanilla extract until smooth and fluffy.

Assemble the Cakes:

1. Once the cake is cooled, cut it into small rectangles or circles using a cookie cutter.
2. Spread a layer of filling onto half of the cake pieces, then top with the remaining pieces to create sandwiches.
3. Freeze for 15 minutes to firm up before coating.

Coat & Decorate:

1. Melt white chocolate with coconut oil or shortening in a microwave-safe bowl in 30-second intervals, stirring until smooth.
2. Dip each cake sandwich into the melted white chocolate, coating it evenly. Place on a parchment-lined tray.
3. Melt dark chocolate and drizzle or pipe thin stripes over the coated cakes to create the classic zebra pattern.
4. Let the coating set at room temperature or refrigerate for 10 minutes before serving.