In small bowl, sift together flower, cocoa, and baking powder. 

Line a baking sheet with Gefen Parchment. On floured counter, roll dough to 6 millimeters (~1/4 inch) thickness. Cut into rounds with biscuit cutter. Fill each round with a dollop of chocolate chip cookie dough (as with all hamantaschen, less filling than you’d think). Shape as you would traditional hamantaschen, pinching corners together tightly. I often mix the leftover yolk with a splash of water and use it as glue to help the corners stay tight. Rest in refrigerator while you preheat the oven.

Heat oven to 350 degrees. Top each hamantaschen with a sprinkling of flaky sea salt. Bake for 10-12 minutes. Let cool for five minutes on baking sheet and then transfer to wire rack to cool completely.

In medium bowl, whisk or beat egg, egg white, and sugar until pale and combined.  Add oil, milk, and vanilla.  Beat until smooth. Slowly add in the dry ingredients. Mix until just combined. 

Pat dough into a round, cover, and rest in the refrigerator for one to two hours or freezer for 30 minutes.