When the dough has thoroughly chilled and you're ready to bake the cookies, centering 2 racks in the upper and lower third of the oven and preheat to 350 (F). Line two baking trays with parchment paper, or, preferably, a Silpat mat.
Start with one disk of dough from the refrigerator. If it is too firm to roll easily, leave it on the counter for 5 to 10 minutes before you begin rolling. Lightly flour your surface and roll the dough into a 12-inch circle, before using an offset spatula to spread 1/4 cup Nutella and 1/4 cup Speculoos over the surface of the circle. Once the Nutella and Speculoos have been spread evenly, use a pizza slicer to cut the dough into 16 wedges, starting by cutting the dough into quarters, and then cutting each quarter into 4 triangles. Starting at the base of each triangle, roll the dough up so that the cookie becomes a little crescent shape. Arrange the crescents on one baking sheet, making sure the points are tucked underneath the cookies, and refrigerate the baking sheet containing the cookies while you roll out the second disk of dough. Repeat steps 2 and 3 for the second disk of dough, this time spreading the remaining 1/3 cup of Nutella over the dough circle as well as scattering 1/4 cup dried cherries evenly over the surface.
In a small bowl, whisk together 1 large egg and 1 teaspoon cold water. Use a pastry brush to spread the eggwash glaze over each crescent, before sprinkling 2 tablespoons granulated sugar over the cookies.
Bake the cookies for 20 to 25 minutes, rotating the cookie sheets from top to bottom at the midway point (I rotated mine at 12 minutes). Bake until they are puffed and golden, before turning out on to wire racks to cool. The cookies are best served warm, around 20 minutes or so from the oven.