Prepare a miniature muffin tin by lining it with paper muffin tin liners. Set aside.
Combine all of the ingredients in a large microwave safe bowl and microwave in bursts of 25 seconds stirring in between each burst for 15 seconds until the mixture is completely melted.
Stir until ingredients are completely smooth and then spoon evenly into prepared miniature muffin tin.
If desired, melt the additional 1/3 cup white chocolate chips in the microwave (in bursts of 20 seconds, stirring in between each burst) and then transfer to a plastic bag. Snip off the tip with scissors and "pipe" a design on top of the (still melty) cookie butter cups.
Allow to harden in the fridge or at room temperature.