In a large bowl using a hand mixer or the bowl of your stand mixer using the whisk attachment, whip cream until stiff peaks form (about 10 minutes)
In a separate bowl mix together condensed milk and vanilla. Fold through the whipped cream until well combined. At this stage if you wanted to add any extras such as crushed Oreos, chocolate chips or other colours or flavours, add them now too.
Pour into a freezer proof container and freeze for at least 6 hours or until firm. Store in the freezer.
Chocolate Chip Cookies
Preheat the oven to 180°C/350°F and prepare two baking trays with baking paper or silicone liners. Set aside.
Melt the butter in a large pyrex jug in the microwave or in a large pot on the stove.
Add the sugars to the melted butter and whisk together. Add the egg and vanilla and whisk again.
Add the flour, baking soda, salt and chocolate chips and mix together well until all ingredients are incorporated.
Spoon 24 even sized scoops onto the prepared baking trays - I like to use a small ice-cream scoop to make sure they are all the same size.
Bake for 8-10 minutes until cookies are just starting to go brown. Allow to cool on the tray for 10 minutes and then transfer to a cooling rack.
Match up the cookies in pairs with another one that is similar shape and size to it (this makes the sandwiches look more uniform. Place them together and freeze for about an hour until firm. This will make it easier to assemble the sandwiches.
To assemble ice cream sandwiches
Prepare a tray or container that can go back into the freezer with the assembled ice cream sandwiches on it. Remove the cookies and the ice cream from the freezer.
Place a scoop of ice cream on the flat side of one of the cookies (enough to almost cover the cookie). Take the matching sized cookie and place it on top, and gently squeeze together. Place the sandwich back on the tray and into the freezer. Repeat with all remaining cookies.
Freeze until the ice cream has firmed up and then roll each sandwich in sprinkles or chocolate chips if desired. If you are serving them individually, this is a good time to wrap them in glad wrap or baking paper and then put them back in the freezer until ready to serve.