Preheat oven to 375º.
Generously grease muffin tins.
Brown onion and ground beef in skillet over low to medium heat until no pink remains.
Use a hamburger chopper to break meat down in small pieces while frying.
Drain well.
Add barbecue sauce.
Continue cooking over low heat until sauce thickens.
Cool completely.
Set aside.
Combine flour, baking powder, onion powder and parsley in a small mixing bowl.
Add milk and egg.
Whisk ingredients until combined.
Stir in shredded cheese and beef mixture.
Allow mixture to stand and absorb for 10 minutes.
Divide beef mixture among 9 muffin tins.
Cut each cheddar cheese string into 3 even pieces.
Press the cheese piece into the center of each muffin.
Cover with batter.
Bake at 375 º for 19-21 minutes, or until lightly browned and mixture puffs up.
Allow puffs to cool abut 10 minutes before removing from tins.
Remove muffins from tins.
Garnish with a pickle or pickle slice on top.
Secure with toothpicks.
Place Cheeseburger Puffs on a serving platter.
Drizzle with additional barbecue sauce, to serve.