Prepare the specified ingredients.
Thoroughly wash the lemon. Remove the zest, it is convenient to do this with a vegetable peeler. Pour water into a small saucepan, add the zest and bring to a boil. Cook for about 5 minutes. Add sugar and wait for it to dissolve completely.
1 pcs lemon, 200 g water, 50 g sugar
Meanwhile, pour gelatin with cold water and leave for 5 minutes.
5 g gelatin
Drain the lemon liquid without the zest from the saucepan into a deep bowl. If the zest is fine, it is advisable to strain the liquid through a sieve. Let it cool for a couple of minutes. Squeeze the softened gelatin and add it to the lemon liquid. Stir until completely dissolved.
Squeeze 25 grams of lemon juice from the lemon and add it to the bowl. The mixture will noticeably lighten from this.
Cool and beat with a mixer until fluffy. Transfer the foam to individual molds. You can use ramekins, glasses, and low glasses. Place in the refrigerator to stabilize for at least 4 hours, or preferably overnight. Depending on the degree of whipping, the mixture may slightly separate and a thin layer of lemon jelly will form at the bottom, and on top there will be a delicate foam.
Lemon mousse is ready. Enjoy your meal!