The amounts in this recipe barely make enough dough for a tin have the size indicated. I used a scale for all measurements and there is definitely...

This is a recipe for lebkuchen, which normally starts out a bit closer to a dough than a batter. You can often pat it out easier than spread it out. But I did notice that the recipe calls for icing sugar. American powdered sugar is what we'd normally translate that to, but in this case it can cause trouble. German icing sugar is just very finely pulverized sugar, and doesn't have cornstarch in it. Ours does. So if used, the cornstarch would suck up all the available moisture and leave you with a really dry mixture. No sweat. Add in milk, a spoonful at a time, until it is something you can more easily spread/pat out in the pan. It may end up a bit drier than intended, but still plenty yummy for coffee, tea, milk, or cocoa. Next time you make it, whirl your sugar in the processor until it's powdered and use that instead. Any extra can be used as you would otherwise, in frosting or for sweetening drinks.