You can find the eggless butter less lemon curd recipe here. (so far, I have stored them for up to 40 days in refrigerator)
Steps
In a wide bowl or measuring jar, add 4 tbsps of lemon curd.
Then add water and rose syrup.
Using a hand whisk, combine them thoroughly.
Check the taste and depending on your preference add sugar. I added about 2 tbsps.
Refrigerate and Serve chilled. Add ice cubes just before serving.
Notes
Adjust the sugar as per your preference. Instead of rose syrup, you can add your favorite flavors. As I prepared the lemon curd with corn starch, I noticed that the starch gets deposited on the bottom. Either you can discard or mix/shake once before serving. It did not alter the taste.