In a saucepan, whisk eggs, sugar, lemon zest and juice. Cook stirring over low heat for 5 minutes. Add the butter cubes one by one and mix well until it thickens. Remove from heat and let cool.
Cut large strips of parchment paper. Wrap around individual souffle molds and secure with elastic bands.
Soften ice cream using a mixer, add the lemon mixture. Pour into the souffle molds and freeze for 2 hours.
Carefully remove the parchment paper. Sprinkle with icing sugar and serve.