Combine chicken, patis, black pepper, granulated seasoning and kalamansi juice in a bowl. Mix the ingredients until well coated then marinate for 30 minutes.
Heat cooking oil in a pan about 1 inch deep and fry the chicken until golden brown. Strain to remove excess oil and set aside.
In the same pan, remove the cooking oil and leave about 1 Tbsp. in the pan. Herat the oil and saute garlic until fragrant.
Add the chicken and saute for a minute. Pour the pineapple juice and add sugar and salt. Stir and bring the liquid into a boil.
Simmer for 30 minutes until slightly thick. Add in the sliced pineapples and pour also the liquid from the canned sliced pineapples.
Continue cooking until the sauce is thick. Turn off heat and serve hot. Enjoy!