I found the perfect recipe for my Hessian Soldier mold thanks to a comment from @kathiquilts suggesting he would make Springerle cookie. I searched and found a recipe but I like the same auther's Traditional Speculoos Cookie better (also called Windmill Cookie). She illustrates how to use a mold like mine only hers are wooden.
The recipe calls for Baker's Ammonia (Ammonium Bicarbonate) and I have never heard of this but it's an essential ingredient to prevent the cookies from becoming too hard. I searched google and Whole Foods has it. She explains this on her blog post with recipe here. She walks you through every step with numerous photos. Enjoy. Save this recipe for the holidays.
xo