First, you need to prepare fresh lychees. So remove the skins and seeds and place the flesh in a measuring cup.
Then take a muddler or the top of a wooden spoon and mash the lychees until you make juice. Ideally, you want a cup of fresh lychee juice.
Place a strainer over a medium pot and pour the mashed lychee mixture into the strainer. What about the pulp, just eat it. The reason why I suggest using a muddler instead of a blender is because the pulp is still enjoyable, but less sweet.
Add ¾ cup of sugar and a cup of water to the lychee juice in the pot.
Now we’re going to boil this mixture over low-medium heat on the stovetop until it starts to bubble. Then turn it down. Ans set aside for cooling. to low and continue to simmer, stirring occasionally, until the sugar is dissolved. Once the syrup thickens and can lightly coat the back of a spoon, you can remove the pot from the heat.
Grab the sealable container of your choice and a funnel and then pour the lychee syrup into the container.
Notes
If you find small foams and bubbles on top. Remove them.