In a large mixing bowl, combine the semolina, all-purpose flour, and powdered sugar.
Add the melted butter and mix well until the mixture resembles coarse crumbs.
Gradually add the milk (and ground mahlab if using), mixing until the dough comes together and is smooth and pliable. If the dough is too dry, add more milk, one tablespoon at a time.
Cover the dough and let it rest for at least 1 hour.
In a saucepan, melt the butter over medium heat.
Add the finely chopped dates and cook, stirring constantly, until the dates are soft and form a paste.
Stir in the ground cinnamon, ground nutmeg, ground cloves, ground cardamom, and orange blossom water or rose water (if using). Mix well.
Remove from heat and let the filling cool.
Preheat your oven to 350°F (175°C).
Take a small piece of dough and roll it into a ball (about the size of a walnut).
Flatten the ball in your hand to form a small disc.
Place a teaspoon of the date filling in the center of the disc.
Fold the dough over the filling and pinch the edges to seal, then shape it back into a ball.
Press the filled dough ball into a ma'amoul mold or use your fingers to create a patterned design. Tap the mold gently to release the shaped cookie.
Place the shaped ma'amoul on a baking sheet lined with parchment paper.
Bake in the preheated oven for about 15-20 minutes, or until the edges are lightly golden. The cookies should not brown too much.
Allow the ma'amoul to cool completely on a wire rack.
Dust generously with powdered sugar before serving.
Enjoy your meal!