Weigh or measure the dark and white sugar into a bowl and set aside. In another bowl, weigh or measure the flour, baking powder, salt, cornstarch, and run a whisk through to blend.
With a stand or handheld mixer, add the butter and sugars. Start on low speed, then increase till you have reached a medium speed. Continue at medium speed for 2 to 3 minutes. Stop and scrape down the sides and add the vanilla extract. Crack the egg into a small bowl to ensure no eggshells are added, then add the egg to the mixing bowl. Blend on medium speed until the egg is incorporated. Turn the mixer to a low speed and gradually add the flour mixture. After all the flour is added, I stop the mixer and scrape down the sides and across the bottom. Turn the mixer on for another 30 seconds to get the last of the flour mixture incorporated into the cookie dough. Stop and add the chunky chocolate chips, dried cherries, and pecans and turn the mixer on for a few seconds. The batter is thick, so you may have to mix a little by hand.
Preheat over to 350° and line 2 cookie sheet pans with parchment paper. Taking a regular teaspoon, spoon out a nice rounded amount, and drop it onto the cookie sheet pan. I got 12 to a pan. These will be irregular-looking cookies but goes with the name Chunky! This also gives the cookies a unique look, and no two will be alike. I stick the whole cookie sheet pan with the unbaked cookies on them into the refrigerator for 5 to 10 minutes before popping them into the oven. Bake for 10 to 12 minutes and really start checking after 10 minutes. You do not want to see and dark brown around the bottom edges of the cookie. They should be light to medium brown on the bottom, mainly due to the dark brown sugar. move to a cooling rack once you have taken them from the oven. They firm up after they cool.