Lemon Curd

Into a heat–proof bowl, firmly grate zest of lemon. Squeeze lemon and pour lemon juice into bowl. Stir in the sugar. Cut butter into small pieces and add to the other ingredients. Set bowl over a saucepan one quarter filled with simmering water and stir until butter has melted and sugar is dissolved. Strain eggs into lemon mixture. Cook gently, stirring constantly 10–15 minutes until mixture is thick and creamy. Pour into clean, warm jars and seal while hot. Keep in refrigerator.