1. Put a little salt on the lemon to wash off the fruit wax on the surface
2. Cut into slightly thicker lemon slices and remove the seeds inside, otherwise it will have a bitter taste
3. Put sugar and salt in the pot, then put the lemon slices in the pot and cook for one to two minutes to reduce the bitterness and astringency
4. Take out the lemon slices and control the water
5. Boil the lemonade and pour it out, pour lemon slices directly into the pot, add sugar and water
6. After boiling, there will be a little froth on the surface, so skim it off
7. Bring to a low heat and cook slowly, you can use a spatula to move a few times in the middle to prevent the pot from sticking
8. Until the sugar water becomes very thick, take out the lemon slices
9. Put the lemon slices directly into the baking tray, put it into the preheated oven, 90 degrees for 120 minutes
