To a saucepan add brown sugar, water, and cinnamon stick. Bring to a boil, reduce heat and simmer until all sugar dissolves. Remove from heat, allow to cool. Remove cinnamon stick.
For the filling:
In a small bowl stir together brown sugar and flour, set aside until ready to use.
For the dough:
In a large bowl combine flour, baking powder and salt. Add lard or vegetable shortening and cooled syrup. With hands mix ingredients until dough comes together.
Transfer dough to a lightly floured work surface and knead dough for about 8 minutes or until smooth. Wrap dough in plastic film and chill for 10 minutes.
Preheat oven to 350 degrees. Line two baking sheets with parchment paper. Lightly beat together egg and water.
Transfer dough onto a lightly floured surface and roll out dough to about 1/4 inch thick. Lightly dip circle cookie cutter into flour, cut and place 2 inches apart on baking sheet. Spoon 2 teaspoons of filling on top of half the circles and top each with another circle over. With finger gently press to seal cookie. With a fork gently pierce each cookie, lightly brush with egg wash and sprinkle with sugar.