Slow Cooker Sweet BBQ Chicken

1 tbsp butter
1 shallot
1 tbsp ground ginger
1 clove garlic
7.5 oz Coke Zero
3/4 cup ketchup
2 tbsp lemon juice
2 tbsp Worcestershire sauce
2 tbsp steak sauce
2 tbsp brown sugar 
1/2 tsp pepper
2 boneless, skinless chicken breasts

Melt the butter in a saucepan and add in the shallot, ginger, and garlic. Saute for about 3 minutes.
Stir in the Coke Zero and bring to a boil.
Stir in the ketchup, lemon juice, Worcestershire sauce, steak sauce, brown sugar, and pepper, and again bring to a boil. Reduce heat and simmer for about 5 minutes or until slightly thickened. 
Place the chicken breasts in a slow cooker and pour the sauce over the meat.
Cook on low for 8 hours, or until the chicken is cooked through. 
Shred if desired and top with additional sauce.