I learned this recipe at school in my home economics class many, many years ago. It was such a hit, it was my job to make these on every special occasion. They are very tart with the lemon juice. You can use either fresh squeezed lemon or lemon juice from the bottle. I find that fresh lemons are a hit and miss with the strength of the tartness so I generally use the bottled juice. If you use fresh, you can also grate some lemon peel into the filling.