No-Bake Chocolate-Covered Mini Roll Cakes

Instructions

For the Cake:

1. Place the chopped chocolate in a microwave-safe bowl. Heat in 30-second intervals, stirring between each interval until melted and smooth. Set aside to cool slightly.
2. In a large bowl, crumble the cake into fine crumbs using your hands.
3. Add the melted chocolate and 3 tablespoons of milk to the crumbled cake. Mix initially with a spatula, then knead with your hands until a dough forms. If the mixture becomes too dry and crumbly, gradually add more milk, one tablespoon at a time, until the dough reaches a soft consistency that doesn't stick to your hands. 
4. Divide the dough into two equal parts and set aside at room temperature.

For the Filling:

1. Combine the softened butter, powdered sugar, salt, vanilla extract, and milk in a medium bowl. Beat with a mixer until smooth and creamy.

Assembling the Cake:

1. Place half of the cake dough between two sheets of plastic wrap or parchment paper. Roll it out to approximately 7x16 inches (18x40 cm).
2. Spread half of the buttercream filling evenly over the rolled-out dough.
3. Roll the dough tightly from the longer side to form a log about 16 inches (40 cm) long, using plastic wrap or parchment paper to help.
4. Repeat the process with the other half of the cake dough and filling. Wrap both logs in plastic wrap and refrigerate for 3-4 hours until firm.

Coating the Cakes:

1. Melt the dark chocolate in a microwave-safe bowl in 30-second intervals, stirring until smooth. If using candy melts or compound chocolate, no tempering is required. If using couverture chocolate, follow the tempering instructions on the package.
2. Remove the cake logs from the fridge. Trim off the uneven ends and slice each log into approximately 9 equal pieces, yielding about 18 cake rolls in total.
3. Place a cake roll on a fork and dip the bottom into the melted chocolate. Use a spoon to pour chocolate over the top, ensuring it is completely covered. Tap the fork on the side of the bowl to remove excess chocolate. 
4. Place the coated cake on a baking sheet lined with parchment paper. Repeat for all cake rolls.
5. Allow the chocolate coating to set at room temperature, or place the rolls in the fridge for about 5 minutes until firm.
6. Melt the white chocolate in a microwave-safe bowl in 30-second intervals, stirring until smooth. Transfer the melted white chocolate to a small piping bag and cut a tiny hole at the tip. Drizzle over the cake rolls to create decorative patterns.