I reckon on around 100g flour with 1/4 tsp psyllium and around the same amount of yoghurt... but it will depend on the thickness of your yoghurt so just add it and mix until you have
a lovely dough to work with.
Don't be discouraged — as soon as you add the first egg,
your lovely dough will separate.
And check out the Kale and Feta Braid I made from
this lovely dough!
I added Greek yogurt for extra protein and it yielded
a lovely dough.