Place the butter and sugars into a bowl and beat on medium until pale and fluffy, approximately 3 minutes with an electric mixer.
Add the egg and continue to beat until well combined, beating for a further minute.
Toss in the flour, baking powder and baking soda and combine until no dry portions remain in your bowl.
Add ¾’s of the crushed Oreos and chocolate chunks and stir until combined and strewn through your cookie dough.
Cover and refrigerate for 1 hour.
Preheat your oven to 180C/350F and line a baking tray with greaseproof paper.
Remove the dough from the fridge and allow to come to a temperature where you can scoop a piece of dough.
Roll the top of your cookie dough into the remaining ? of chocolate chunks, flattening slightly as you place it on the tray.
Continue scooping and rolling into the remains chocolate chunks, pressing flat light when you place onto the tray, ensuring there is 1 ½ inches between each cookie.
Press a few of the remaining Oreo chunks into the top of your cookies.
Bake for 14 minutes or until golden at the edges.
Allow to sit on your baking tray for 3 minutes before placing on a cooling rack.
Serve with a glass of milk.
Dig in and enjoy!