1. Preheat oven to high-broil.
2. Butterfly shrimp and lay on sheet pan.
3. Place pepperoni on top of shrimp, add about 1 tsp caramelized onions and 1 tsp parmesan cheese.
4. Broil for 5-7 minutes on the middle to high rack of the oven. Remove as soon as shrimp is no longer translucent and cheese has melted.
5. Garnish pepperoni shrimp bites with parsley and serve.