Mix the flour, baking soda, cinnamon, and salt in a medium bowl. Set that aside for now.

In another large bowl, use a stand or hand mixer with a whisk attachment to beat the unsalted butter at medium-high until it's smooth (~ 1 minute). Add granulated and brown sugar and keep beating until the mixture is creamy (~ 2 minutes).

Add the large eggs, vanilla, and molasses, and beat at high speed 'til everything is well combined (~ 1 minute). Scrape the bowl's sides and bottom to get everything mixed in.

Gradually add dry ingredients (Step 1) to our wet mixture, mixing at low speed until combined. Toss in oats and chocolate chips (both types) while the mixer is still running low. Our dough should be dense and sticky at this point.

Cover the cookie dough and let it sit in the fridge for 45 minutes to 3-4 days, then take it out to room temperature (~ 30 minutes).

Preheat your oven to 350°F. Line your baking sheets with silicone mats or parchment paper. Scoop out the dough (about 3 tbsp per cookie) and spread it on your baking sheets, leaving about 4 inches between every two cookies.

Bake for 13 to 15 minutes until the sides are lightly browned. The center parts will still look super soft.

Let them sit for about 5 minutes on their baking sheets (out of the oven), then move them to the rack to chill completely.

(Optional): While they still feel warm, press extra chocolate chips on top. Enjoy your chewy cookies!