Preheat the oven to 350*. Line a 8x8 nonstick baking dish with parchment paper and set it aside.
In a heat safe small bowl, add the chocolate chips and the oil. Microwave for 45 seconds. Stir the chips and oil, return to the microwave and heat for another 10 seconds. Stir until the chips and oil are smooth. Set it aside.
Using a medium size mixing bowl, whisk together the ½ cup all-purpose flour, granulated sugar, baking soda and salt. Set it aside.
In a small bowl, whisk together the eggs, vanilla extract and milk. Add to the flour mixture. Now add the melted chips and stir until the batter is just combined. (make sure to let the chocolate chip mixture cool before adding, otherwise it will seize up.)
Toss the chopped peanut butter cups with 1 tablespoon of flour. Fold the coated chopped peanut butter cups into the batter. Mix just until all ingredients are combined.
Pour the batter into the prepared baking dish.
Using a 1 - 1 ½ tablespoon cookie scoop, or a regular tablespoon, dollop the peanut butter on top of the brownie batter. Use a knife to swirl the peanut butter. Bake for 30 minutes. Allow the brownies to completely cool before cutting.
If you really want an even more rich brownie, add up to 1 cup of the chopped peanut Buttercups.
You can also use semi-sweet chocolate chips instead of milk chocolate.
You can serve this topped with ice cream...YUM!
Storage: Keep any leftovers in an airtight container for up to 4 days.