Preheat oven to 350°F. Line three baking sheets with parchment paper.
In a stand mixer, beat butter together with the sugar until light and fluffy, about 4 minutes. You’ll need to scrape down the bowl a few times. Beat in the eggs one at a time. Beat in the vanilla extract. Turn off the mixer.
Add the flours, cinnamon, baking soda, and salt in a big pile on top of the butter mixture. Use a fork to combine all of the dry ingredients as much as possible. This just prevents us from having to dirty up an extra bowl! Turn the mixer back on, on low speed, and beat flour mixture into butter mixture. When it is almost, and only small flecks of flour remain, turn it off immediately! You do not want to overmix, the cookies will get tough!
Add the oats, raisins, and chocolate chips. Turn the mixer back on, on low speed, for just a few turns of the paddle until the oats, raisins, and chocolate chips are incorporated.
Spoon the dough out by the heaping tablespoon onto the baking sheets, leaving at least an inch and a half between cookies. Sprinkle with flaky sea salt if desired (DO IT!!!).
Bake until cookie edges turn brown but the centers are still very pale and soft looking, 10 to 13 minutes. Allow to cool slightly on the pan, then transfer to a wire rack to continue cooling.
Store in an airtight container at room temperature for up to 5 days, or freeze!