Combine chicken, calamansi juice, salt and pepper in a bowl. Marinate the chicken for 1 hour.
Coat the chicken with cornstarch by putting it in the plastic back and shake it until well coated. You can also just dredge the chicken with the cornstarch in a bowl if you don't want to use plastic bags.
Heat oil in a frying pan about 3 cups then fry the chicken until golden brown. Place on a paper towel lined plate and set aside.
To make the chicken crispier, you can refry the chicken in high heat for a few seconds then set aside again.
Heat another empty pan or wok and melt the butter. Then put the garlic and saute until fragrant.
Turn off heat and add the spring onion and siling labuyo then stir. Let it cool for 2 minutes then add in the parmesan cheese. Stir until well mixed.
Add in the chicken and toss it well until the chicken is well coated with the parmesan-butter mixture.
Transfer to a serving dish and serve it with honey mustard dressing or garlic mayo dip as sauce. Enjoy!