I replace the expresso powder with cocoa powder because coffee doesn't go over well with anyone else but me.
For S'mores Hamantashen I added one egg and about 1/2 a cup of flour, then filled with a chocolate coin (left over from Hannukah) and topped with a mini-marshmallow. Jack says more marshmallows are necessary. I say it's very sweet; probably need to use flour instead of confectioners sugar while rolling out, or maybe a blend. Also, they came out flatter than a normal hamantashen, but I liked it anyway.