Place the cream, condensed milk, espresso powder and cocoa powder into the bowl of your stand mixer. Using the whisk attachment, whip on medium speed for 2-3 minutes until soft and voluminous - the mixture should stand in soft peaks.
Pour one third of the mixture into a 2 lb loaf tin (or other similarly sized vessel). Mix together the hazelnut butter and the chopped hazelnuts. Dot a third of this mixture over the top of the ice cream and swirl using a skewer.
Repeat this process twice more, using the remainder of each mixture. Sprinkle a few extra chopped hazelnuts on top, if liked.
Place the tin into the freezer and freeze for 6-8 hours or overnight. Serve in chocolate-dipped waffle cones, sandwiched between chocolate chip cookies or simply eat with a spoon! And don't forget to top with a good dollop of hazelnut butter and some extra chopped hazelnuts.
If you don't have a stand mixer, you can use a large mixing bowl and an electric hand whisk - it just might take a little longer. I would so recommend the KitchenAid mixer though - it's an absolute workhorse in my house, making everything from ice cream to bread! Recipe adapted from Nigella Lawson.