Juice the lemons.

Heat about 1 cup (250 mL) of water, but do not let it boil.

In a large bowl, pour in the hot water, add the lemon juice and sugar, and stir until the sugar is completely dissolved.

Finely grate the zest of one lemon and add it to the mixture. Add the remaining water and mix well. Place in the freezer.

Tip: It's best to use a container with a lid and take it out of the freezer about 20 minutes before serving so you can scoop it easily, or freeze it directly in individual containers with lids.