Preheat and prep: Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
Cream butter and peanut butter: In a large mixing bowl, beat the butter (or shortening), peanut butter, brown sugar, and granulated sugar together until light and creamy, about 2-3 minutes.
1/2 cup unsalted butter, 3/4 cup creamy peanut butter, 1/2 cup dark brown sugar, 1/2 cup granulated sugar
Add wet ingredients: Beat in the egg, egg yolk, milk, and vanilla until smooth and combined.
1 large egg plus 1 egg yolk room temperature, 2 Tbsp. whole milk, 1 tsp. vanilla extract
Mix dry ingredients: In a separate bowl, whisk together the flour, cocoa powder, baking soda, espresso powder, and salt.
1 cup all-purpose flour, 1/2 cup unsweetened cocoa powder, 1/2 tsp. baking soda, 1/2 tsp. espresso powder, 1/4 tsp. salt
Combine ingredients: Gradually add to the wet ingredients, mixing on low speed until a soft dough forms. Note: The dough will be very soft! You can chill the dough to make it a little easier to work with, but it’s not necessary.
Shape & roll: Scoop dough into 2 tablespoon-sized balls. Roll each in granulated sugar and place 2 inches apart on the prepared baking sheet. Since it’s a soft, slightly sticky dough, it’s easy to handle once rolled in a little granulated sugar. If you feel like you need to add a couple more tablespoons of flour, only add 1-3 tablespoons. I don't want the cookies to turn out cakey for you.
Bake: Bake for 8–10 minutes, or until the edges are set but the centers still look soft. Start Timer
Add chocolate: Immediately press a Hershey’s Kiss into the center of each cookie, and you’ll see those classic crinkles form. Allow cookies to cool on the baking sheet for 5-8 minutes before transferring to a wire rack to cool completely and garnish the cookies with any reserved granulated sugar, if desired. The cookies are soft and brownie-like - and SO good frozen too!
20 Hershey’s Kisses, mini peanut butter cups, or Rolo’s