Preheat oven to 350.
Leaving rind on, cut lemon into small chunks.
In blender puree lemon chunks, eggs, butter, vanilla & sugar til mixture is smooth & creamy. It should be fairly runny.
Pour into piecrust.
Bake for 40 min. If crust becomes too brown, cover gently with foil.
Serve with dollop of fresh whipped cream.