Preheat the oven to 375°F (190°C). Grease cookie sheets. Or use baking paper.

In a large bowl, mix together the cake mix and flour. Stir in the eggs and water to form a stiff dough.

On a lightly floured surface, roll the dough out to 1/8" thickness. Cut into 3" round circles and place 2" apart onto the prepared cookie sheets. Place a teaspoon of filling into the center of each cookie and pinch the sides to form three corners. Use egg wash with extra egg.

Bake for 20 to 25 minutes in the preheated oven, or until lightly browned. Allow cookies to cool for 1 minute on the cookie sheets before removing to wire racks to cool completely.