Melt the butter, add the condensed milk, sift the cocoa, add the malt powder (optional), vanilla and salt.
Whisk it all together and add the crushed biscuits. I like a lot of biscuits in mine, you can use less if you like.
Make 2 logs using baking paper. Roll them very tightly and freeze for 4 hours at least (put the rolls in a bag and seal it).
You can keep them in the freezer for up to 6 months, but who are we kidding they’ll be gone in no time. Sahtein!