Depending on the consistency of the sunflower seed butter you are using,
add additional coconut flour until the filling becomes a wet dough.
Resist to add
an additional coconut flour or your batter will be too thick and the cake will turn out to be dense.
The mixture was really sticky so, in a separate bowl, I put
some additional coconut flour and proceeded to coat the bars and shape them.
Even before I added the egg, the mixture was like a pancake batter, and
the additional coconut flour didn't help.