I start by mixing butter, garlic, and parsley in a small bowl. Then, I melt it in the microwave for about 30 seconds until it’s smooth. Let it cool slightly before spreading on the bread.
Heat olive oil in a skillet over medium heat. Add the thinly sliced red onions and cook for 2 minutes until soft. Then, add the minced garlic and cook until fragrant, about 30 seconds.
Add shredded chicken, paprika, Worcestershire sauce, and BBQ sauce to the skillet. Stir to combine and cook for 2-3 minutes until heated through and well-coated with sauce.
Lay 12 slices of bread on a flat surface. Spread the garlic butter on each slice, then turn them buttered side down. Place 6 slices of cheese on half of the bread, top with an equal portion of BBQ chicken, then add the remaining cheese and top with the other bread slices.
Heat a large non-stick skillet over medium heat. Place the sandwiches in the skillet and cook until the bottoms are golden brown, about 3-5 minutes. Flip the sandwiches, reduce heat to medium-low, and cook another 3-5 minutes until the cheese is melted and the other side is browned.