Put 2 clean jars to warm in a slow oven while you make the curd.
Put the lemon juice and rind in a medium microwave-able bowl. Stir in the sugar and butter, cut into small pieces.
Microwave, stirring often, until the butter and sugar are melted but the liquid is not too hot-about 60 seconds.
Whisk in the eggs vigorously in a thin, steady stream until very well combined. Give the whole a quick whisk. Microwave on full for 2 minutes without opening the door. Remove and whisk very well. Allow to stand for 1 minute.
Microwave on full for another 1 minute.
Spoon into the warmed jars. Allow to go completely cold before sealing.