This recipe is by Lois Ellen Frank, from her book Foods of the Southwest Indian Nations (Ten Speed Press, 2002). Both the venison and the juniper berries are available from mail-order sources. Of course, grape juice or wine would not have been available to the Maya, but Lois has adapted this recipe for the modern kitchen.
In Australia, we use a long loaf of Turkish bread for these sandwiches, but you can use Mexican bolillos or even Kaiser rolls. As you might expect, the sauce is the secret ingredient. The sandwiches can be assembled, wrapped in plastic wrap and refrigerated overnight for grilling the next day if desired.