Heat some oil in a pan and brown the chicken on all sides.
Add the onion, garlic, and ginger and sauté briefly until fragrant.
Add the sweet soy sauce, brown sugar, sambal, chili sauce, peanut butter, and ketchup. Stir well, then add the water and let it simmer gently for about 5 minutes.
Stir in the cornstarch slurry and let the sauce thicken for a few more minutes.
Meanwhile, cook the rice according to the package instructions.
Serve the spicy chicken with rice, cucumber salad, cassava crackers, atjar, and seroendeng. Enjoy!