In a large bowl, whisk together the flour, granulated sugar, cinnamon, ground ginger, baking soda, cloves, salt, and allspice.
In a medium skillet, melt the butter over medium heat and cook, swirling the pan often, until it starts to bubble and foam, about 3 minutes. Cook, stirring continuously, until brown flecks appear, about 2 minutes more.
Pour the browned butter into a medium bowl and whisk in the grated ginger and molasses. Let cool for 15 minutes, whisking occasionally, then whisk in the egg. Pour the butter mixture into the dry ingredients and use a wooden spoon to stir until just combined. Flatten the dough into a disc, wrap it in plastic wrap, and refrigerate for at least 1 hour.
Preheat the oven to 350F. Line a large baking sheet with parchment paper.
Dust a clean work surface with flour, then roll half the cookie dough into a 1/4-inch thick sheet. Use your spider cookie cutter to cut out around 16 spiders. Reserve the scraps.
Place the cookies onto the prepared baking sheet, leaving space between each one. Place the baking sheet in the fridge while you roll out the rest of the dough.
Press the dough scraps into the other half of the cookie dough. Place a piece of parchment paper the same size as a baking sheet on your work surface and roll the dough directly on the parchment into a 1/4-inch-thick round. Slide the parchment onto a second baking sheet (you aren't cutting cookies out of this portion). Remove the baking sheet from the fridge and sprinkle the cut cookies and uncut dough round with the turbinado sugar.
Place the baking sheet with the uncut dough round on the lower rack and the cut cookies on the upper rack and bake for 15 minutes, rotating the pans front to back midway through baking, until the cookies have puffed and no longer feel tacky. Remove the baking sheet with the cookies from the oven and move the large uncut cookie to the upper rack; set the sheet of cookies on a wire rack and let cool. Bake the large uncut cookie until puffed and no longer tacky, about 10 minutes more. Remove the baking sheet from the oven, set it on a wire rack, and let the large cookie cool completely, about 30 minutes or more.
Break the baked cookie round into large pieces and put the pieces in a large resealable plastic bag. Seal the bag and use a rolling pin to crush the cookie pieces into fine crumbs. You should get about 4 cups of crumbs. You can also use a food processor, if that's easier for you!