The potato dough should ideally have the consistency of cookie dough, but be slightly harder. If your dough feels softer than it should, you can add in some more sugar. Remember that the dough tends to dry up pretty quickly, so you’ll have to stay quick. To make sure the dough doesn’t turn soft in the first place, remember to allow the potatoes to cool down completely after they have been boiled, and then mash them. Mashing warm potatoes will cause them to get moister than you’d want them to.