Make the cheesecake filling

• Mix the cream cheese, powdered sugar, vanilla and green food coloring until smooth.
• Scoop tablespoon portions onto parchment paper.
• Freeze until firm.

Make the cookie dough

• Beat the butter, brown sugar and white sugar until creamy.
• Mix in the egg and vanilla.
• Add the cocoa, flour, cornstarch, baking soda and salt and mix until a thick dough forms, then stir in the chocolate chips and black food coloring if using.

Stuff the cookies

• Divide the dough into portions.
• Flatten each piece of dough, place a frozen cheesecake filling in the center and completely wrap the dough around it.
• Roll into a ball and place on a parchment-lined baking sheet.

Bake

• Bake at 175 °C until the edges are set but the centers still look soft.
• Let cool on the pan.

Decorate

• Melt the white chocolate and tint some with purple and some with green gel food coloring.
• Drizzle the purple and green chocolate over the cookies and immediately top with Halloween sprinkles.