In a saucepan, combine sugar, water and cook until the temperature reaches 120 degrees. For this, it is better to have a special kitchen thermo. If this is not the case, then boil the sugar with water until a syrupy state.
Place the gelatin in a bowl of cold water, let it swell for 5-10 minutes, then heat (in a water bath), stirring occasionally, to dissolve the gelatin. Then add it to the syrup.
Then remove the resulting mass from the heat, add lemon juice, beat thoroughly with a whisk.
Fill the prepared form with the mass and refrigerate for several hours.
Then cut the marmalade into squares and sprinkle with sugar.
If children help you, then give them molds in their hands – let them cut out the future marmalade themselves.