1/2 cup unsalted butter, at room temperature
3/4 cup granulated sugar
1/2 cup brown sugar
1 tablespoon vegetable oil
2 tablespoons light corn syrup
1 egg
1 teaspoon vanilla
3/4 cup plus 2 tablespoons all-purpose flour
3/4 cup cake flour
1/2 cup unsweetened cocoa powder, preferably Hershey's Special Dark
1/2 teaspoon baking soda
3/4 teaspoon baking powder
1/4 teaspoon salt
1 cup peanut butter baking chips (I use Reese's) OR chocolate chips
1 cup chopped peanut butter cups (I use Reese's dark chocolate miniatures) OR Rolo candies, frozen
Beat the butter for a minute or so by hand or (even better) with an electric mixer. Dump in both sugars and beat another minute or so until light and fluffy. Beat in the oil, vanilla, corn syrup (which will slide right out of the tablespoon if you measured the oil first), and egg. Beat just until incorporated. Beat in the cocoa powder carefully so you don't end up with a cocoa cloud all over your kitchen. Whisk together the remaining dry ingredients (flour-salt) and dump on top of flour mixture. Beat in just until incorporated. Gently fold in the peanut butter chips OR chocolate chips and chopped peanut butter cups OR frozen Rolos.
Cover and chill the dough for about 15 minutes while you preheat your oven to 375 degrees. Also, line a baking sheet with parchment paper.
Roll dough (about 1-2 tablespoon portions) into balls and place on cookie sheet, about 9-12 to a sheet. Bake at 375 degrees for 6-7 minutes, or until just starting to crack at the edges. Remove from oven and cool on the sheet for 2 minutes. Remove cookies to a wire rack to cool completely if you're storing them (in an airtight container, please). I maintain that most homemade cookies are not worth eating after about 1 day of storage at room temperature, so if you want to keep these longer, I'd throw them in the freezer.
http://guiltychocoholicmama.blogspot.com/2016/03/national-chocolate-chip-cookie-week_49.html