Cut butter into flour. Add half cup of water, then add up to another half cup, until dough barely holds together. Roll out dough, fold, and turn. Repeat 3 times, refrigerating between turns to keep dough cold. When done, let rest in fridge for ~30 minutes.

Mix dry ingredients, then add wet ingredients. Result should be a thick paste.

Divide pastry in four, then roll out until thin. Wrap pastry around filling, and arrange on cookie sheets. Beat egg white, then brush on top. Sprinkle sugar overtop.

Bake at 450 degrees for 15-20 minutes, until golden. Let cool before even thinking about cutting into slices. Good day-of, even better after drying for 2-3 days. Later results unavailable, samples eaten.