3/4 cup (175 grams) granulated sugar, plus more for dusting
1/2 cup (113 grams) unsalted butter, at room temperature
2 large eggs
1 teaspoon pure vanilla extract
Crushed peanuts, for sprinkling (optional)
Flaky sea salt, for sprinkling (optional)
Preheat the oven to 350°F. Line baking sheets with parchment paper.
In a medium bowl, whisk together the flour, baking powder, and kosher salt.
In a stand mixer fitted with the paddle attachment, cream the peanut butter, brown and granulated sugars, and butter on medium speed until well combined. Add the eggs one at a time, mixing on medium speed until creamy. Mix in the vanilla. Add the flour mixture and mix on low speed just until combined.
Scoop 1 1/2 tablespoons (or use a #40 scoop) and place the balls about 2 inches apart on the prepared baking sheets. Dust with granulated sugar, then use a fork to press the balls into 1/4-inch-thick rounds. Sprinkle with crushed peanuts and/or sea salt, if using.
Bake the cookies until light brown on the edges, about 15 minutes. Allow to cool for 5 minutes on the baking sheet, then remove to a wire rack to cool.