Add your double cream and condensed milk to a large bowl.
Whisk on a low-medium speed until the ingredients are smooth and even.
Turn the whisk up a bit higher and whisk until the mixture is starting to thicken and is lovely and smooth - It doesn't need to be extremely thick, it just needs to be smooth and starting to thicken.
Alternatively, you can whip the cream up to soft peaks, and fold the two ingredients together.
Add in your finely crushed oreo biscuits - I crush them in my food processor - but you can use a bowl with a rolling pin, or a sandwich bag or something!
Fold the oreo crumbs through until combined!
Add 1/3 of your ice cream mix to your tin/tub and swirl through 1/3 of the chopped oreos
Repeat twice more so all the ingredients are used up.
Put the tub/tin your freezer till frozen and firm and enjoy!