Instructions:

Prepare the crust:

1. Preheat the oven to 325°F (165°C). Line a muffin tin with 6 paper liners.

2. In a small bowl, mix chocolate cookie crumbs, sugar, and melted butter until well combined.

3. Press the mixture evenly into the bottom of each muffin liner. Bake for 5 minutes and set aside to cool.

Prepare the cheesecake filling:

1. In a mixing bowl, beat cream cheese and sugar until smooth and creamy.

2. Add the egg and vanilla extract, mixing until fully combined.

3. Divide the filling into two bowls. In one bowl, mix in the cooled espresso and cocoa powder to create the mocha layer.

Assemble the cheesecakes:

1. Spoon alternating dollops of vanilla and mocha filling over the crust in each liner.

2. Use a toothpick or skewer to gently swirl the two flavors together, creating a marble effect.

Bake:

1. Bake the cheesecakes for 18-20 minutes, or until the centers are set but slightly jiggly.

2. Let them cool to room temperature, then refrigerate for at least 2 hours.

Decorate and serve:

1. Drizzle chocolate ganache over the top of each cheesecake and garnish with chocolate shavings before serving.