Flour can be from winter wheat or summer wheat – they have different properties which can explain why some doughs held together and others did not. Also, flour dries out when you store it too long. Always add a little moisture, water, milk, etc. when you get a crumbly dough – you are merely replacing the moisture that was lost.
Healthy chocolate brownies
Heat the oven to 190C/170C fan/gas 5 and line a shallow 23cm square baking tin with baking parchment. Tip the beans, cocoa, coffee granules, xylitol, vanilla, eggs and yogurt into a large bowl. Blitz using a hand blender until smooth. Or, do this in a food processor. Add the baking powder, then blitz again.