Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Cream together the butter and both sugars until light and fluffy.
Mix in the egg and vanilla extract, then add blue food coloring until it reaches Cookie Monster blue.
In a separate bowl, whisk together flour, baking soda, and salt.
Add the dry ingredients to the wet mixture and stir until combined.
Fold in chocolate chips and crushed Oreos.
Scoop the dough into balls and place them on the baking sheet.
Bake for 9–11 minutes or until the edges are just golden.
While warm, press candy eyes and mini cookies into the tops.
Cool on the baking sheet for a few minutes before transferring to a wire rack.