Preheat oven to 350F degrees. For easiest removal, line an 8x8-inch baking pan with parchment paper and then spray with the non-stick baking spray.
Press the premade sugar cookie dough evenly into the bottom of the prepared pan.
Bake for 30-35 minutes, until the bars start to turn a light golden brown. Be careful not to over bake the cookie dough.
Allow the cookie bars to completely cool before moving to the next step.
Pour the white chocolate chips into a microwave-safe mixing bowl. Microwave the chocolate chips for 30 seconds, stir, and then cook again for another 10-20 seconds. Continue doing these steps until the chocolate chips are completely melted.
Once melted, fold the peanut butter into the melted white chocolate and stir until well combined.
Pour the mixture onto the top of the cooled sugar cookie bars. Set aside.
In another microwave-safe bowl, melt the semi-sweet chocolate chips in the microwave for 30 seconds. Stir the chocolate and cook again for another 10-20 seconds; repeat this and continue stirring between each cook time.
Using a spoon, drop random streaks of chocolate all over the top of the peanut butter mixture.
Then, using either a knife or toothpick, make swirl patterns all over the top until the desired look has been achieved.
Cover the bars with foil and set in the fridge for a few hours to allow the chocolate to harden.
When it’s time to cut the bars, set the pan out for 10-15 minutes to bring them to room temperature. Slice into 16 bars.
Store covered in an airtight container at room temperature or in the fridge.
Notes
You'll want to purchase sugar cookie dough that is pre-made. It will be in the refrigerated section of your grocery store where the other cookie dough is located.
You can use your own favorite sugar cookie dough recipe if you prefer.
Don't over-bake the sugar cookie base. You don't want the edges to be too brown.
If you don't enjoy peanut butter, then just leave it out. This recipe will still work.
These bars will be easiest to remove if you line the baking dish with parchment paper first. In a pinch, you can just spray the pan with nonstick baking spray (I like the kind with flour in it - like Baker's Joy.)