1. Prepare ingredients: lemon, sugar and rock sugar.
2. Wash the lemon, wipe off the fruit wax on the epidermis with salt, cut it into thin slices and remove the seeds.
3. Put the lemon peel into the toaster and add sugar and rock sugar.
4. Cover with plastic wrap and put it in the refrigerator overnight (12 hours or more) to pickle pectin.
5. Take it out and steam it in a steamer 1 hour, then take it out and pour it into a bread maker.
6. Turn on the jam function, naturally cool it after boiling, and put it into a sealed bottle without water and oil, which can be kept for one month at room temperature.