If you haven't read the post below, then read it before this one, or it'll make no sense.
Read it? Ok, good.
I googled. Here's what I found.
(a) I'm spelling it wrong, it's Choco-leibniz.
(b) The headquarters are indeed just behind my hotel here in Hannover. Yay.
(c) According to google translate, "Leibniz" means, um, "Leibniz".
(d) They are over a hundred years old and "the biggest family biscuit enterprise in the World".
There are no suggestions or instructions on the corporate website about the correct way to eat them. I take from this, that I do it right.