I love that it's named "Lemon Cream" but has no cream in it. That sort of name seems more true of dishes back then than nowadays -- they seemed to use "cream" to indicate texture, while we are more likely to use it to indicate a milk product.
They're right about the lemon tart thing -- very similar to a recipe I have for mini-tarts. And much like a cake filling I make, too, now I think on it.