To make the dough: In a large bowl, use a flexible spatula to stir together the brown sugar, melted butter, molasses, vanilla, and salt. Smear the mixture against the bottom of the bowl to smooth it out and eliminate any lumps.  , Add the egg and stir until combined. Add the flour, spice, baking powder, and baking soda and stir with the spatula until fully incorporated and no dry spots remain.  , Cover the bowl and refrigerate for 1 to 2 hours. The dough will firm up as it chills. , When you are ready to bake, preheat the oven to 350°F with racks in the upper and lower thirds. Line 2 baking sheets with parchment.   , To coat the cookies: In a medium bowl, whisk together the confectioners’ sugar and spice.   , One at a time, scoop the dough into 1 3/4" balls (about 40g each; a level jumbo cookie scoop works well here), drop into the confectioners’ sugar mixture, and toss to coat. Transfer the cookies to the prepared baking sheets.   , Bake the gingerbread crinkle cookies for 15 to 18 minutes, rotating the baking sheets top to bottom and front to back halfway through, until puffed and set in the center and firm around the edges. , Remove the cookies from the oven and allow them to cool completely on the baking sheets.  , Storage information: Store leftover gingerbread crinkle cookies in an airtight container at room temperature for several days; freezing is not recommended.