Grease a 18 cm (7 inch) spring form pan and line it with a circle of baking paper. Cut two large rectangular sheets of the baking paper and line the sides as well. Wrap the bottom of the pan in two big pieces of aluminium foil - this is required as during the baking the butter of the crust might melt and leak out of the pan.
Crush the cookies into fine crumbs using a food processor or in a plastic bag with a rolling pin.
In a bowl combine cookie crumbs, cocoa powder, sugar and melted butter. Mix until all ingredients are combined. Press the crust into the bottom of the prepared pan. Place the pan in the freezer while preparing the filling.
Preheat oven to 160 degrees C (320 degrees F)
In a large bowl using an electric mixer beat cream cheese and powdered sugar until creamy. Add eggs and beat until smooth. Add starch, orange juice, zest and vanilla extract and beat shortly, until combined.
Pour the filling into the crust. Bake for 60-70 minutes or until the centre of the filling is set and the edges of the cheesecake start getting golden brown. Switch off the oven, open it halfway and let the cheesecake cool for 30 minutes inside. Remove the pan from the oven and let it cool to room temperature. Cover with cling film or aluminium foil and refrigerate for 6-8 hours.
Cover with the glaze before serving.
Melt chocolate in a heatproof bowl over a pan of gently simmering water (double boiler). Add milk and stir until combined.
Pour the glaze over the cheesecake. Spread evenly with a spoon or a metal spatula.
Decorate the cheesecake with candied or chocolate covered orange peels.