Line a large baking sheet with parchment paper or wax paper or nonstick foil.
Put 2 tablespoons of semisweet morsels in a freezer type zipper bag or a disposable decorating bag and set aside.
Melt remaining semisweet morsels in a microwave-safe bowl on high power for 45 seconds; Stir and repeat until fully melted. Spread the melted semisweet chocolate in a thin layer across the baking sheet and let it sit while you prepare the white morsels.
Melt white morsels in a microwave-safe bowl. You can use 50% power and stir at 1 minute intervals, or use high power and stir at 30 or 45 second intervals. I prefer using a lower heat with white morsels. Stir the peanut butter into the melted white morsels.
Drizzle peanut butter mixture over top of set semisweet chocolate. Sprinkle crushed Butterfinger or Butterfinger Baking Bits over top and press down lightly to adhere.
Microwave the reserved 2 tablespoons morsels in heavy-duty freezer plastic bag on high power for about 20 seconds; knead until smooth. Cut a tiny corner from bag; squeeze to drizzle over bark.
Chill for 1 hour before breaking apart and serving. Store refrigerated in airtight container.