In a large bowl add the cream, milk and sugar, beat on medium speed for 20 seconds.
Pour the mixture into the ice cream maker, using a spatula to get all the ingredients.
When the ice cream is almost finished churning (in the last 5-10 minutes) add the Nutella and crushed Oreo cookies, and continue until it reaches desired creaminess, (see ice cream maker instructions) mine took 30 minutes. Depending on when you add the Nutella your gelato will have either a chunkier Nutella addition or a more incorporated Nutella addition.
Transfer the mixture to a freezer safe container. If needed freeze for a couple of hours to firm up.
Notes
Superfine sugar or Caster sugar is basically granulated sugar that is extremely fine. You can make it at home, just place the granulated sugar in a blender or food processor and blend or pulse until fine, be careful not to blend too much or you will be making powdered sugar.Homemade ice cream / gelato should be kept in the freezer, in an airtight container. Apparently glass or stainless steel are the best containers to use. It will keep for at least one week in the freezer.