Line an 8x8” (9x9” for thinner cookies) pan with foil and spray with cooking spray. Or just spray with cooking spray (no foil required).
Cream butter and both sugars until combined.
Combine flour, baking soda, and salt in a medium bowl. Stir and set aside.
Turn mixer on low. Add egg, mixing completely. Mix in vanilla extract. Add flour mixture to the wet ingredients and mix until combined. Mix in 1 cup chocolate chips. Press into prepared pan. Chill dough for 15 minutes.
Preheat oven to 350°. Bake bars for about 20-28 minutes, until the top is golden. I like my cookies on the underdone side, so mine baked for 23 minutes. Let cool completely.
Place Oreos and cream cheese in a food processor and run until the mixture forms a ball (30-60 seconds).
Place pieces of the Oreo truffle mixture on top of the cooled cookies and press with your hands to flatten into an even layer.
Heat 1 cup of chocolate chips with 2 teaspoons of Crisco in a microwave safe bowl on HIGH power in increments of 30 seconds, stirring in between each, until melted and smooth. (The shortening is optional, but it will help your chocolate cut without breaking.)
Pour over the top of the Oreo truffle layer and spread evenly. Chill until set, a few hours.
To minimize the chocolate cracking when cutting, let the bars come to room temperature before cutting.
