Add the Rice Chex cereal to an extra large mixing bowl and set aside.

Place the chocolate chips, peanut butter, and salted butter in a microwave safe bowl.

Microwave on high for 1 minute, then stir until the mixture is completely melted and smooth.

Stir in the vanilla until fully combined.

Slowly drizzle the warm chocolate peanut butter mixture over the cereal.

Gently fold the cereal with a spatula until all pieces are evenly coated without crushing them.

Add the 15 crushed Butterfinger bars to the coated cereal and gently stir to distribute the candy pieces.

Sprinkle the sifted powdered sugar over the cereal mixture in 2 to 3 additions, gently tossing between each addition until all pieces are well coated and no longer sticky.

Spread the Butterfinger Puppy Chow in a single layer on a parchment lined baking sheet and let it cool until dry to the touch.

Transfer the cooled puppy chow to a serving bowl and sprinkle the remaining 3 roughly chopped Butterfinger bars over the top before serving.