Make the filling:

• In a small saucepan over medium-low heat, combine the dates, water, and salt. Cook the dates, mashing and stirring until they have broken down into a paste (about 3 minutes). Let cool.

Make the dough:

• Preheat the oven to 325°F (165°C) and line two baking sheets with parchment paper. Set aside.
• In a mixing bowl or in a food processor, combine the flour, sugar, and baking powder, then pulse or cut the butter in.
• Combine the milk and rosewater and then stir into the dough until it comes together.

Assembling the Maamoul:

• Gather the dough together, and then divide the dough into 20 equally-sized balls.
• Take one ball of dough, flatten it in the palm of your hand and pinch it into a bowl shape.
• Place a teaspoon of filling in the center of the dough and bring up the sides and pinch together to seal the filling in.
• Roll and flatten slightly, and then place the cookie seam side down on the prepared cookie sheet. Repeat with the remaining dough and filling.
• Prick the top of the cookies with a fork or toothpick in a decorative pattern, and then bake until the cookies are just beginning to turn golden, about 25-30 minutes. Dust generously with powdered sugar while the cookies are still warm.
• Store cooled cookies in an airtight container at room temperature for up to 3 days.