Instructions
Step 1
Toast the peanuts: Position a rack in the center of the oven and preheat to 350°F.
Step 2
On a baking sheet, drizzle the peanuts with the oil, season with salt, and toss to coat, then spread in an even layer. Roast the peanuts, tossing occasionally and rotating halfway through, until they are a rich dark brown, 18–20 minutes. Remove and set aside until cool. (If the nuts are close to overtoasting, transfer to a plate to cool.)
Step 3
Make the dough: In a small bowl, whisk together the eggs and vanilla until well-combined. In a medium bowl, stir together the all-purpose flour and sorghum flour until well-combined.
Step 4
In a stand mixer fitted with the paddle attachment, beat the butter at medium speed until it is softened but still cold, 2–3 minutes, stopping to scrape down the sides of the bowl with a silicone spatula as needed. Add the peanut butter, sugar, and dark brown sugar and beat on medium until the mixture is light and fluffy, 2–3 minutes. Add the baking soda, salt, and baking powder and beat on medium speed for about 15 seconds to incorporate. With the mixer on medium, gradually add the egg mixture until fully incorporated. Add the flour mixture and mix on low speed for about 30 seconds until no flour is visible. Use a silicone spatula to scrape the bowl’s sides and bottom to ensure that all ingredients are fully incorporated. Cover with plastic wrap and refrigerate until the dough is chilled and firm, at least 30 minutes.
Step 5
Position one rack in the top third of the oven and one in the bottom third, and preheat to 375°F. Line two baking sheets with parchment paper.
Step 6
Shape the cookies: To a small wide bowl, add enough sugar for rolling the balls of dough. Scoop a heaping tablespoon of the chilled dough per cookie and roll into 1½-inch balls. Roll the balls in the sugar to coat, then place on the prepared baking sheets, leaving at least 1½ inches between cookies, with 12 cookies per sheet. (Cover the remaining dough with plastic wrap and return it to the refrigerator between batches.) Press your thumb in the center of each ball of dough, turning as you press to create a round dent. Spoon ½ teaspoon of peanut butter into each dent and generously sprinkle with flaky salt.
Step 7
Bake the cookies until they have spread out, about 4 minutes. Remove from the oven and pile a heaping tablespoon of peanuts (about 15–20) in the center of each cookie. Return to the oven and bake, switching and rotating the pans halfway through, until the cookies are golden brown and puffed, 4–6 minutes. Remove and reshape any misshapen cookies, and add peanuts to cover any gaps in the topping. Cool completely on the baking sheet before serving.