Put 50g granulated sugar into the milk pot and cook over low heat until golden.
Turn off the heat, pour in 60ml (about 1 tbsp + 1 tbsp) boiling water to convert the syrup, and stir with chopsticks（ Be careful when pouring, the syrup will splash suddenly.) If the water is not hot enough, the syrup will agglomerate when it is cold. At this time, turn on the low heat again and cook slowly until it dissolves.
When the syrup has not hardened, pour it into the jelly mold, shake it gently and let the bottom of the mold be covered with syrup. Then put it in the refrigerator to make the syrup hard (if you don't make the syrup hard, just pour it into the custard, the syrup will mix with the custard).
Wash the milk pan, then pour in 40 grams of fresh milk and sugar and heat it to 80 degrees (i.e. when you see the heat coming out of the pan, don't bring it to a boil, otherwise the egg yolk will turn into flower).
First, beat the yolk into egg liquid with a hand beater, then slowly add it into the warm milk, and stir it evenly with the beater.
Take out the softened gelatin slices and put them into a steel basin. Put 1 teaspoon of water into it. Heat it to liquid state. Pour it into the custard sauce and stir well. Remove the jelly mold with syrup from the refrigerator and pour in the mayonnaise. Then move it into the refrigerator and refrigerate for one night.