Preheat oven to 325 F
Spay a 10 inch cast iron skillet with nonstick cooking spray
Using a stand or hand mixer, beat sugars and butter together until creamy
Add milk, egg and vanilla and continue beating until blended
In a separate bowl, combine flour and baking soda
Add flour mixture to butter mixture slowly, beating on low until well combined
Add semisweet chocolate chips and 1/2 of the peanut butter chocolate candies until well incorporated
Spoon batter into skillet as evenly as possible
Scatter remaining peanut butter chocolate chips on top of batter
Bake for 45-50 minutes, or until golden brown and set
Serve warm - enjoy!