Whisk together the flour, cornstarch, baking soda, salt, and cinnamon.
In the bowl of a stand mixer fitted with the paddle attachment or with a hand mixer, beat the butter until creamy. Add the white and brown sugar and beat until combine and fluffy, 1-2 minutes. Scrape down the bottom and sides of the bowl. Add the egg, vanilla, and honey and beat to combine.
Add the oats and M&Ms and mix gently just until combined. Try not to overmix at this point.
Cover the dough(eat some it is sooooo good), and refrigerate for a half hour.
Preheat the oven to 345 F/ 175 C.Drop balls of dough(about 1 1/2 Tablespoons per cookie) onto a baking sheet fitted with parchment paper. Bake for 7-8 minutes. Cookies will cook a bit more and set while cooling. I like mine extra chewy so i take them out at 7 minutes, while the centers still look a tad undercooked.Store at room temperature in an airtight container.