In a small bowl, combine onion powder, paprika, garlic powder, Old Bay seasoning, salt, and pepper.
Spread seasoning mix generously on each chicken breast and place in crockpot. Pour in Root Beer and add barbecue sauce.
Cook on low for 8 hours, remove the chicken and shred with two forks. Return chicken to crockpot.
Mix it thoroughly with the barbecue sauce, and cook for another 15-30 minutes until sauce is more absorbed.
Place chicken on rolls, cover with about 1/4 cup of cheese, add caramelized onions, and sprinkle with fresh cilantro.
In a medium skillet, melt butter over medium-high heat. Add onions and garlic.
Saute until translucent. Reduce heat to low, and cover and cook for up to 30 minutes, stirring occasionally.
Compliments of 365 Days of Baking and More