Squeeze the lemons and filter the lemon juice.
Pour it together with the water in a pot, mixing it with the sifted starch.
Add the sugar to the mixture, place the pan on the stove over medium heat, and mix.
When the lemon frost reaches its boiling point and has a sticky consistency, remove it from the heat and let it cool in the molds.
Once it becomes lukewarm, transfer the lemon frost into the refrigerator for as long as it takes more or less the consistency of a pudding.