I was also thinking of those egg biscuit cookies, but they are too light colored to be like lembas.
Do you mean springerle? Ever had those? They're rather hard, crisp cookies, baked until just golden brown, mildly sweet and flavored with anise. We have those every Christmas - Mom had a special rolling pin that put a pattern on them, then we'd cut them into squares and dry overnight before baking. I love them! And because they're hard, they travel VERY well...she used to send them to me in Germany.