In a double boiler over simmering water, combine lemon juice and peel, butter and sugar, stirring until butter has melted. Add beaten eggs to lemon mixture, stirring constantly with a wooden spoon. Continue to stir over medium to low heat until mixture is quite thick, it should coat the back of the spoon. (Be careful not to over cook or it will separate.) Remove from heat.

Pour into sterilized canning jars (the curd will thicken as it cools), seal and refrigerate. Keeps up to 1 month.

Makes about 3 cups.