I finally looked at the recipe, I have made this cake too...
And it's really good! I think part of the problem some had, besides not following the recipe and leaving out ingredients, is actually knowing how a butter cake should be constructed.
The recipe isn't explicit, but it does say "Beat sugar, butter and lemon peel in large bowl until light and fluffy. Add eggs 1 at a time, beating well after each addition. Beat in lemon juice"
I don't know about the people who got the hockey pucks, but those instructions for me meant at least 15 minutes of beating time with a Kitchen Aid. By the time the last egg and lemon juice went in, the mixture was about the texture of mousse. That makes a huge difference, beating in enough air, for how this type of butter cake will turn out. Also, setting the butter out the night before so that it truly is room temp butter that is being beaten, and not cold hard butter that is just not going to whip up right.
Another vote for the recipe!
Interesting related side note: My neighbor loves old style pound cake and has tasted mine. And I do the old pound of butter, sugar, eggs, flour and flavoring. She has tried to make them and has literally thrown out 5 cakes during a baking session because they were rocks, and she was using leavening and milk in hers. I told her to come over and we would bake pound cake. After I had been beating eggs and butter for about 20 minutes, she was very concerned. She just wasn't letting the butter and eggs whip into an airy fluff before proceeding. That is key.