Line a 7 inch/ 18 cm spring form pan with a circle of parchment paper. Adjust the oven rack to middle position. Place a pan full of cold water on the bottom.

Preheat the oven to 320º F/ 160º C.

In a bowl combine the graham cracker or cookie crumbs with the butter. Mix well and press the crust onto the bottom and part of the sides of the prepared pan.

Place the pan in the fridge while preparing the filling.

In a large mixing bowl beat together cream cheese and icing sugar with an electric mixer until smooth. Add vanilla and starch and beat again shortly until absorbed.

Add the eggs and beat for a few seconds, just until combined.

Divide the filling in two parts (one can be slightly bigger than the other). Using a rubber spatula, gradually add the melted chocolate to the smaller part. Mix until uniform.

Pour small quantities from each mixture into the prepared pan, alternating them several times. When both mixtures are used, smooth the top with a spatula.

Bake the cheesecake for about 1 hour or until the top is set.

Let it cool 20 minutes inside the oven with the door open. Then allow to cool until room temperature before transferring it to the fridge.

Chill for 6-8 hours.

Whip the cold heavy cream with the icing sugar. Use a piping bag and a star tip to pipe on the cheesecake.

Optionally top with rainbow sprinkles before serving.