It also calls for unsalted butter and a "pinch" of salt. I'd like to add more than a pinch. May I? My intuition is saying this will be tastier with vanilla and more salt. Am I crazy?
You can do whatever you want. After all, you're the one who is going to eat it, not us.
There shouldn't be any structural problems, if that's your concern. Baking isn't quite as precise as it's often painted- most ingredients in most recipes have quite a bit of leeway.
Will alcohol-based vanilla curdle the chocolate? (I don't think it will if I add it to the beaten egg/sugar mixture).
No, no, vanilla, alcohol and chocolate are frequently combined in thousands of recipes (perhaps millions).
Clarification: I am bringing this to a Dessert Party and was asked specifically to make a flourless chocolate cake. If I add 1 tsp. vanilla and 1/2 a tsp. salt will it not taste "classic?"
You should, however, present it as a variation of the original recipe if anyone asks. Also, things depend some on the type of chocolate used- if it's sweetened it very likely contains vanilla already.
Definitely add the vanilla to the egg mixture and the extra salt is up to you. I'm not sure what you mean by classic, but these additions, won't change the flavor by much.
Thanks so much, everyone! I added both but was conservative with quantities. If it is delicious I will post it, it was so easy to make.
I would add the vanilla too. I don't think there would be any structural problems with the cake.