Mix corn flour and water in a bowl and keep it aside

Add lemon juice to the pan. Since my lime juice was quite tart, I used 1/3 cup, you can use 1/2 cup

Add Sugar to the pan. Depending on the tart level of the lemon, you can adjust the sugar

Now add lemon zest, I have added 1 teaspoon, you can add upto 2 teaspoon

Now stir well over low medium heat until sugar dissolves

Add corn flour slurry to the pan and mix well

Bring the mixture to boil

Add butter to the pan and mix well

Keep cooking the mixture until it turn glossy and starts thickening

Remove the pan from the heat

Add condensed milk and mix well

Add 1-2 drops of lemon yellow colour and mix well. This is optional step. The market based lemon curd has yellow colour so you can add food colour to the curd

Pour the curd in in sterilized air tight container, wrap top with cling wrap, once it cools to room temp, remove the wrap, cover with lid and refrigerate. Use it within a week. If you freeze the curd, you can use it for 2 months

Use this delicious lemon curd for mousse, tarts, pastries or as substitute for jams