In a saucepan, mix 2 tbsp lemon zest, 4 tbsp lemon juice, 2 eggs, 2 egg yolks, and ½ cup granulated sugar with a silicone spatula or whisk until smooth. Add ¼ cup unsalted butter slices on top.
Turn heat to low and continuously mix until butter is melted. Keep stirring on low heat, making sure to scrape the bottom and sides of pan, until lemon curd thickens and can coat the back of a spoon. Immediately take pan off heat.
Pass lemon curd through a fine mesh sieve into a heat-proof bowl. Cover with cling wrap (to avoid a skin from forming) and chill in the fridge for 1 hour.
Remove cling wrap and lemon curd is ready to use!
Notes
Tip: Cook on low heat while constantly stirring to avoid making lemon scrambled eggs!
Storage: Store lemon curd in an airtight container in the fridge for up to 2 weeks, or freezer for up to 1 year. Make sure to leave enough space in the container if freezing, since the liquid will expand and can break the container. I like to use freezer-safe baggies and thaw the curd in the fridge overnight.