Preheat the oven to 375°F. Line 2 cookie sheets with parchment paper or silicone baking mats. Whisk the all-purpose flour, cake flour, cornstarch, baking soda, baking powder, and salt together in a mixing bowl. Set aside.
3/4 cup all-purpose flour, spooned and leveled, 3/4 cup cake flour, spooned and leveled, 1 tsp. corn starch, 1/2 tsp. baking powder, 1/2 tsp. baking soda, 1/2 tsp. salt
Cream the butter, sugars, and peanut butter together in the bowl of a stand mixer fitted with the paddle attachment for ~2-3 minutes or until creamy and smooth.
1/2 cup cold, unsalted butter, cubed (8 Tbsp.), 1/2 cup brown sugar, packed (light or dark), 1/4 cup granulated sugar, 1 cup creamy peanut butter, like Jif or Skippy
Then add in the egg, egg yolk, vanilla extract, and milk. Blend until mixed. If any of the mixture gets stuck on the paddle attachment or sides of the bowl, use a rubber spatula to knock it off.
1 large egg, 1 large egg yolk, 1 tsp. vanilla extract, 1 Tbsp. milk (optional)
Keep the mixer on low speed and gradually add in the dry ingredients. I add in about ¼ cup at a time.
Add in the peanut butter chips until incorporated and then turn off the machine.
1 (10 oz.) bag peanut butter chips (I use Reese's brand) ~2 cups
Note: you can bake the cookies straight away, or you can chill the cookie dough at this point for a few hours or up to 3 days.
Scoop the cookies with a cookie scoop. I make these cookies about 2-3 Tbsp. in size, but you can make them smaller if you want; adjust baking time as needed. Roll each cookie dough into a dough ball and roll in granulated sugar.
1/4 cup granulated sugar
Place 6-8 cookies on one cookie sheet at a time. Use a fork to create the criss cross pattern on each cookie. If the edges crack a little when you press down, you can form it back together.
Bake the cookies for ~9-11 minutes Start Timer or until the tops are golden brown. Ovens vary so keep an eye on them. The secret is to pull them out before you think they are done.
Let them rest on the cookie sheet for a few minutes, and then use a spatula to transfer them to a cooling rack carefully. The cookies are very soft right out of the oven. Sprinkle the tops with any remaining granulated sugar and a sprinkle of flaky sea salt. Enjoy!
flaky sea salt (optional)