Pare off the rind from the lemons using a good-quality peeler, taking care not to take off the white pith as well.
Bring a large saucepan of water to the boil and blanch the lemon rind for 30 seconds. Remove and refresh in iced water, then repeat this process 4 more times.
Drain the lemon rind of any excess water in a sieve and then weigh it. Whatever the weight, measure out hal