Cut the chicken into 2 pieces by cutting it between the joint of the wingettes and drumettes. Wash and put in the colander to drain excess water.
Put the chicken wings in empty mixing bowl and season with salt, pepper, calamansi juice and patis. Mix until the chicken is coated with the seasoning and marinnate for 30 minutes to 1 hour.
Prepare a plastic bag and put 2 to 3 pcs of chicken pieces on the bag. Put 1/2 cup of cornstarch in the plastic bag and shake until the chicken is well coasted.
Heat cooking oil in a deep pan and fry the chicken pieces until golden brown. Set aside.
In an empty pan or wok, melt 1 Tbsp. of butter and sauce garlic and onion until soft. Add Worcestershire sauce, 7-Up, brown sugar, black pepper, bay leaves and siling labuyo.
Bring the mixture into a boil until the sauce is slightly reduced. Add cornstarch slurry and stir until the sauce is thick.
Add the fried chicken wings and toss until well coated with the sauce. Serve hot and garnish with chopped spring onios.