Sugar Spun Run's Thick Peanut Butter Chocolate Chunk Cookies

In a large mixing bowl, combine the softened butter, creamy peanut butter, light brown sugar, and granulated sugar. Beat with an electric mixer until light and fluffy.

Add the whole egg, egg yolk, and vanilla extract; beat on medium speed until smooth and incorporated.

In a separate medium bowl, whisk together the flour, cornstarch, baking soda, and salt.

With mixer on low speed, gradually add the dry ingredients to the wet mixture, mixing just until completely combined and no dry streaks remain.

Fold in the chopped chocolate chunks with a sturdy spatula until evenly distributed throughout the dough.

Cover the bowl with plastic wrap and chill in the refrigerator for 30 minutes.

While dough chills, preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper.

Scoop chilled dough into large 2 ½-tablespoon balls, roll gently between your palms to smooth into tall mounds, and place at least 2 inches apart on prepared sheets.

Bake at 350°F (175°C) for 13 to 15 minutes, until the edges are just beginning to turn golden brown and centers are puffed.

Allow the cookies to cool completely on the baking sheet so the tender centers set firmly before serving.