Blueberry Puree: In a saucepan, combine all the puree ingredients, except lemon juice. Over medium heat, while stirring, heat the mixture until thickened. Place in a blender and puree with lemon juice. Cool. Filling: In a food processor or blender with a sharp blade, process the ricotta cheese until smooth. Add cream cheese and eggs. Beat until smooth. Add the remaining ingredients and beat until smooth. Pour the filling over your crust. Drop spoonfuls of the blueberry puree carefully over it. Using a knife, swirl lightly to create a marbled effect.