I wouldn't freeze the rusks once they have been dried. They stay fresh for ages, so there's not much point in freezing them. However, if you want to enjoy freshly baked (soft) mosbolletjies for breakfast, you can freeze the dough once it has been shaped and allowed to rise. Wrap the risen dough balls (in the baking tin) in a layer of tinfoil and then one or two layers of cling wrap. Freeze for up to 6 months. To use, take out of the freezer the night before, leave the rolls in the fridge to defrost overnight and then bake according to the recipe instructions. If you intend to do this I would recommend using disposable baking tins.