In a medium bowl, whisk together the flour, cocoa powder, baking soda and salt until the dry ingredients are evenly combined and no lumps remain.

In the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl using a hand mixer), add the softened butter, brown sugar and granulated sugar. Beat on medium speed for about 2 minutes, until the mixture becomes light in color and fluffy in texture.

Add the eggs one at a time and then the vanilla extract. Continue beating until fully incorporated, scraping down the sides of the bowl as needed to ensure everything is well blended.

Reduce the mixer speed to low. Gradually add the dry flour mixture and beat just until combined — avoid overmixing. Stir in the oats and 1 cup of the chocolate chips, mixing on low speed until evenly distributed throughout the dough. Reserve the remaining ½ cup of chocolate chips for topping the cookies after baking, if desired.

Cover the bowl with plastic wrap and refrigerate the dough for at least 1 hour, or up to 24 hours to enhance the flavor and texture.

When ready to bake, preheat your oven to 350 degrees F. Line baking sheets with parchment paper. Using a cookie scoop or tablespoon, drop heaping spoonfuls of dough onto the baking sheets, leaving space between each cookie. Gently press down the tops of each cookie slightly, as these cookies don’t spread much during baking.

Bake for 8 to 10 minutes, just until the tops are almost set. Avoid overbaking to keep the centers soft. If baking multiple trays at once, rotate the pans halfway through to ensure even baking.

As soon as the cookies come out of the oven, gently press a few of the reserved chocolate chips into the tops of each cookie for a decorative touch. Let the cookies cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.