German Rock Raisin Cookie Recipe

Does anyone have a recipe they would share for traditional German cookies called rock raisin cookies? The back story is that I met a man at a party who mentioned that when he was a little boy he and his grandfather used to make them. (I thought it might be fun to try and re-create them.) He remembered a few things that might help.

• They were giant cookies (as "big as boulders")
• Had a mix of black and yellow raisins in them
• Were similar to a simple butter-based cookies (ie, Lemon Sugar Cookies from America's Test Kitchen) that I made for the party, which had lemon zest in the dough and on the outside (they were rolled in sugar/lemon zest)

I've found a few recipes for rock raisin cookies online but trust that someone in the group has made something authentic, tried, tested, and true (and something not made with lard). Any ideas?

Kind regards,

Arlene