In a medium glass bowl, whisk together the sugar, lemon juice, and egg yolks. (DO NOT use a metal bowl. The lemon juice will react with it.)
Place the glass bowl on top of a saucepan with a couple of inches of simmering water. The water should not touch the bottom of the bowl. You're creating a double-boiler.
Whisk the lemon curd for about 10 minutes until the mixture is thick enough to coat the back of a spoon. Remove from the heat and whisk in the butter one piece at a time until melted.
Pour into a glass jar, cover, and refrigerate until cooled.
Berry Salad
Rinse and dry the fruit. Hull the strawberries and slice them in half. Place all the fruit in a large serving bowl.
In a small bowl, combine the lime juice, honey, and lime zest. Pour over the berries and stir to coat.
Place the berry salad in the fridge for 30 minutes to chill and let the dressing do its work.
To serve, top portions of berry salad with some lemon curd and a little extra lime zest, if desired.
Notes
You can make the lemon curd ahead of time to save on preparation time. It'll keep for up to 1 month in the fridge or 1 year in the freezer. Just thaw the lemon curd for 24 hours in the fridge before using it if you freeze it.