In a large bowl, combine the dry base: Fine semolina, Coarse semolina, and All-purpose flour with a few tablespoons of Granulated sugar, a pinch of Salt, and the warm aromatic spices Ground mahlab and Ground mastic.
Melt together equal parts Ghee and Unsalted butter and pour into the semolina mixture; work it in with your fingers until the mixture resembles coarse crumbs and is evenly moistened.
Bloom the yeast by sprinkling Active dry yeast over warm Milk with a teaspoon of sugar and let sit 5–10 minutes until foamy, then pour the milk-yeast into the semolina mixture and stir to form a soft, slightly sticky dough. Cover and let rest 1–2 hours so the semolina hydrates and the flavors mellow.
Make the date filling by softening Date paste in a bowl with a little melted butter (if desired), then flavor with a pinch of Ground cinnamon, a dash of Ground nutmeg, and a teaspoon each of Orange blossom water and Rose water; adjust sweetness to taste.
For a walnut filling, pulse Walnuts in a food processor until coarse, then mix with a little Granulated sugar, a sprinkle of Ground cinnamon, and a splash of Orange blossom water and Rose water to bind.
For a pistachio filling, finely chop or pulse Pistachios and combine with a small amount of Granulated sugar and a few drops of Orange blossom water and Rose water until the mixture holds together.
To shape: pinch off walnut-sized pieces of dough, flatten into a disc, place about 1 teaspoon of your chosen filling in the center, then fold the dough around the filling and gently roll into an oval or press into a ma'amoul mold to create a patterned surface.
Arrange the filled cookies on a baking sheet lined with parchment, leaving a little space between each. Refrigerate the shaped cookies for 15–20 minutes to help them keep their shape, if desired.
Preheat the oven to 350°F (175°C). Bake the cookies for 15–20 minutes, or until they are lightly golden — take care not to overbake so they remain tender.
Let the ma'amoul cool completely on a rack, then dust generously with Powdered sugar before serving. Store in an airtight container for up to several days; the flavors often improve after a day.
