To the bowl of a stand mixer fitted with the paddle attachment (or large mixing bowl and electric mixer) combine the butter and both sugars and molasses until smooth.
In a small bowl, combine flour, oats, cinnamon, baking soda, salt, and cornstarch.
Add the egg to the butter and sugar mixture. Beat until the egg disappears into the batter.
Slowly add the dry ingredients and mix. Add the dried cherries and chocolate chips and mix until evenly combined.
Cover dough and chill for at least 1 hour or up to 24 hours.
Preheat oven to 350°F. Sit dough on the counter for 10 minutes before scooping and baking. Place a Silpat silicone mat on a half sheet pan.
I used a 4 tablespoon, spring-release scoop for uniformly measure the dough. I baked them for 12 minutes to get perfectly crunchy edges and soft centers. They will cook quicker if you're making smaller cookies.
I recommend you Calibrate your Oven at least once a year to ensure it's baking at the correct temperature.