1 ¾ cups (8 ¾ ounces) all-purpose flour, ½ teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon table salt, 6 tablespoons unsalted butter, melted and cooled, ⅓ cup packed (2 ⅓ ounces) dark brown sugar, ⅓ cup light molasses, 1 large egg yolk, 1 teaspoon ground cinnamon, 1 teaspoon ground ginger, ¼ teaspoon ground allspice, ⅛ teaspoon ground nutmeg
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. In a large bowl, whisk the melted butter, brown sugar, molasses, egg yolk, and spices until well combined and smooth.
Add the flour mixture to the butter mixture and stir with a rubber spatula until no dry flour remains and a soft dough forms (make sure to scrape along the bottom and sides of the bowl to get all of the dry flour). Use your hands to gather the dough together and mush it into a cohesive ball in the bowl.
Lay a large sheet of parchment paper on the counter. Transfer the dough to the center of the sheet and press it into an oval that’s about 8 inches wide.
Lay a second large sheet of parchment paper on top of the dough. Use a rolling pin to roll the dough between the parchment paper into an oval (or blob shape, it doesn’t matter!) that’s ¼-inch thick and about 12 inches wide.
Slide the dough, still between the parchment, onto a rimmed baking sheet. Transfer the baking sheet to the refrigerator and chill until firm, at least 30 minutes and up to 1 day. (The longer you chill it, the more cleanly the cookies will cut out.)
When you’re ready to bake, set your oven rack to the middle position and heat the oven to 375°F.
Remove the baking sheet from the refrigerator and peel off the top sheet of parchment, saving it for later. Use cookie cutters to cut out shapes from the dough, leaving about ½-inch of space in between them and leaving the dough on the parchment paper.
Use a small offset spatula or butter knife to gently loosen the scraps of dough around the cookies. Peel away the scraps and set them aside on a clean counter. If needed, use the spatula to gently rearrange the cookies so there’s at least a ½-inch of space in between them. (If the dough gets too warm and squishy to work with at any point, pop it back in the fridge for 10 to 15 minutes to firm up.)
Place the baking sheet in the preheated oven. Bake until the edges of the cookies are set and the centers are a little soft and puffy, 8 to 10 minutes.
While the first batch of cookies is baking, on a clean counter, squish and knead the dough scraps together into a ball. Lay the sheet of parchment you saved from earlier on the counter and transfer the dough to the center. Use your hands to press the dough into a circle.
Lay a fresh sheet of parchment paper on top of the dough and roll it to ¼-inch thickness. Repeat cutting the dough into cookies, discarding the dough scraps, and spacing out the cookies as needed. Slide the parchment paper with the second batch of cookies onto a second rimmed baking sheet.
When the first batch of cookies is ready, use oven mitts to remove the baking sheet from the oven and place it on the stovetop or a cooling rack. Let the cookies cool on the baking sheet and cool them completely, at least 30 minutes. Meanwhile, repeat baking and cooling with the second batch of cookies.