Prepare the filling: Pulse the walnuts in a food processor until finely chopped (or finely chop them with a knife); set aside.

Put the dates, hot water, and butter in a large skillet and heat over medium heat, mixing and smashing the dates with a fork, until a soft paste-like mixture forms, about 2 minutes. Stir in the cinnamon, cloves and orange zest. Remove from the heat, add the walnuts and orange blossom water, and stir until thoroughly combined.

Transfer the date paste to a plate and refrigerate it for 30 minutes, or until completely cooled.

Meanwhile, prepare the dough: Combine the all-purpose flour, semolina flour, baking powder, and confectioners' sugar in a large bowl. Add the butter and rub it into the flour with your fingertips until the mixture looks like coarse meal. Add the milk and vanilla and stir with a wooden spoon or spatula until the dough begins to hold together.

Transfer the dough to a lightly floured work surface and, using the palms of your hands, knead gently until it becomes smooth, about 1 minute. Shape the dough into a ball, wrap it in plastic wrap, and refrigerate for at least 15 minutes and up to 1 hour.

Remove the cooled date paste from the refrigerator and take 1 heaping teaspoon (about 10 g) and roll it between your palms into a ball. Set the date ball on a large plate and continue with the rest of the filling, making 20 balls total.

Arrange the oven racks in the lower and upper thirds of the oven and preheat the oven to 325°F. Line two baking sheets with parchment paper.

Shape the cookies: Take the dough from the refrigerator and divide it into 20 walnut-sized pieces. Roll each piece into a ball with your hands; the balls should be twice the diameter of the date balls. Gently press your fingertip or the handle of a wooden spoon into one dough ball to create an indentation in the center. Carefully enlarge the indentation by cradling the dough ball in one palm and pinching the edges with the index finger and thumb of your other hand, working around the inside and outside of the dough to form a shell ¼ inch thick. Gently push a date paste ball into the dough shell and press the edges of the dough together over the top of it, gently pinching the dough to enclose and seal in the filling in an even layer of dough and reshaping the stuffed dough into a ball. Repeat with the remaining dough and filling.

Dust your cookie mold lightly with flour. With your palm, gently press a filled dough ball into the mold, unpinched side down. Flip the mold over and tap against the work surface until the menena pops out. Place the cookie decorated side up on one of the prepared baking sheets. Repeat with the rest of the filled dough balls, spacing them about ½ inch apart on the baking sheets.

Bake the menenas until they are firm and pale ivory, 20 to 30 minutes, rotating the baking sheets top to bottom and front to back about halfway through. The cookies should not brown, or they will be hard. Remove from the oven and let the cookies sit on the baking sheet for 1 minute, then carefully transfer them to a wire rack. Dust the cookies generously with confectioners' sugar while still warm and let cool to room temperature.