Preheat oven to 375° F and line 3 baking sheets with parchment paper (or spray with cooking spray).
In standing mixer, mix butter, brown sugar, and cane sugar on medium-high for 2-3 minutes until creamy and slightly lighter in color. Scrape down the sides of the bowl to make sure it is thoroughly mixed. Add the eggs and vanilla extract, and mix on medium speed until it is well mixed. Make sure to scrape down the sides of the bowl.
1 ¼ cup unsalted butter , 1 cup light brown sugar, ¾ cup cane sugar, 2 large eggs, 1 tablespoon vanilla extract
In a separate bowl, whisk together the flour, Oreo crumbs, black cocoa powder, baking soda, salt, and cornstarch. Then add to the standing mixer and mix on lowest setting until there are no pockets of flour. Don't overmix.
2 ½ cup all purpose flour, 2 cup crushed Oreo crumbs, ¾ cup black cocoa powder*, 1 teaspoon baking soda, 1 teaspoon fine sea salt, 1 ½ teaspoon cornstarch
Roll dough into 18 balls and place on baking sheets (6 per sheet) at least 2 inches apart. Bake for about 8-10 minutes, but make sure not to overbake. (These typically are done in 9 minutes in my oven). Leave on the tray until cooled completely.
For the frosting, whip together the butter and cream cheese on high until creamy. Then scrape down the sides of the bowl, add in the heavy whipping cream and vanilla extract, and mix on high for 1-2 minutes. Once well mixed, gradually sift in the powdered sugar**. Gradually increase the speed, and allow to mix on high for 3-4 minutes. Scrape down the sides of the bowl every few minutes. Either spread on cookies with a knife, or pipe frosting after the cookies are completely cooled. Sprinkle Oreo cookie crumbs over the top of each cookie (optional). Enjoy!
6 tablespoon unsalted butter, 8 oz cream cheese, 2 teaspoon clear vanilla extract**, ¼ cup heavy whipping cream, 7 cup powdered sugar***, extra Oreos for topping