This is most likely due to using too much flour and ground almonds. Correct measurements are very important in this recipe and the reason why I highly recommend using a kitchen scale. With the correct amounts, the dough will first look crumbly and dry when you start to mix it but then transforms into a smooth dough as you continue mixing. However, if you are having trouble getting your dough to come together, add up to a tablespoon of water (no more!) and mix until the dough forms.