Yield: 16 cookies
12 tablespoons unsalted butter, at room temperature
1 cup packed dark brown sugar
¼ cup unsulfured molasses (not blackstrap)
1 large egg
2¼ cups all-purpose flour
2 teaspoons baking soda
1½ teaspoons ground cinnamon
1½ teaspoons ground ginger
½ teaspoon kosher salt
Sanding sugar or granulated sugar, for rolling
Preheat the oven to 375°F and line two rimmed baking sheets with silicone baking mats or parchment paper.
Using an electric mixer fitted with the paddle attachment, combine the butter and brown sugar. Beat on medium-high speed until creamy, 3 to 4 minutes. Reduce the speed to low and mix in the molasses and egg until combined.
In a medium bowl, whisk together the flour, baking soda, cinnamon, ginger, and salt. With the mixer on low, gradually add the dry ingredients to the wet ingredients until combined.
Pour some sanding sugar or granulated sugar on a plate. With your hands, roll the dough into balls slightly larger than a golf ball (about 2 ounces; if the dough is sticking to your hands, wet them), then roll each ball in sugar to coat. Transfer to the prepared baking sheets and use the bottom of a juice glass to gently flatten each cookie. Bake, rotating the pans midway through the baking time, until flattened and cracked on top, about 10 minutes. Transfer to a wire cooling rack and let cool in the pan for a few minutes, then use a spatula to transfer the cookies to the rack and let cool completely.