Thanks for your suggestions! We'll add a note to the recipe to add
the lemon zest & juice to taste, especially if your lemon is large.

I had the same problem! I couldn't rectify it with any additions. I think the lemon is a key to the balance in the recipe, but I think the problem is the lemon juice, not the zest. The recipe calls for the juice and zest of one lemon. My lemon was large. Perhaps the recipe should specify the amount of lemon juice, such as 1 or 2 tablespoons. This is where ChefDaddy's suggestion is perfect - next time I make it (and I will!) I will taste as I add increments of the lemon juice. The onions are so luscious that it's worth it to figure out a fool-proof recipe!

I might add more sour cream to tame the lemon zest. Hope this helps!

I don't have an answer but I just wanted to say that this is the problem with following recipe's. I personally wouldn't add any lemon until I tasted it without lemon. I'm sure it's there for balance but it's a dip not a sauce, a side or an entree. And if it were my recipe I wouldn't give an amount I would say " to taste". Just some thoughts of a recipe non-lover.