Sprinkle brown sugar over pork and mix well to evenly coat.
Let sit at room temperature for 10 minutes while preparing marinade.
In a bowl, whisk together remaining ingredients.
Transfer pork into a large sealable freezer bag.
Add marinade, press out excess air from bags, and seal.
Turn bag over several times to ensure beef is evenly coated.
Refrigerate for at least an hour (for pork cutlets/tenderloin) but preferably overnight (especially if using spare ribs).
Heat gas or charcoal grill to medium-hot.
Drain excess marinade off meat.
Grill pork, turning once, to desired doneness, about 3 to 4 minutes per side.
Garnish with thinly sliced green onions, if desired.
Serve whole pieces as a main course or cut into smaller pieces, using kitchen shears, for a starter or party nibble.