01 -
Fill a medium saucepan with 2 inches of water. Bring to a boil over high heat, then reduce to medium-low to maintain a simmer.
02 -
Whisk together lemon juice, lemon zest, sugar, and eggs in a heatproof mixing bowl. Slice the butter into cubes and add to the mixture.
03 -
Place the bowl over the simmering water and whisk continuously for 20-25 minutes until the curd thickens. Check if done by reaching 170°F or coating the back of a spoon.
04 -
Strain the curd through a fine mesh sieve into a glass bowl. Cover with plastic wrap, pressing it directly onto the surface to prevent a film from forming.
05 -
Allow the curd to cool at room temperature, then refrigerate for at least 4 hours or overnight until fully thickened. Store in sealed jars for up to 1 week.