Mix all of the marinade ingredients together in a bowl and mix until consistent and smooth.
Place your pork fillet into a dish and cover in the marinade. Flip it over a few times to make sure it's well covered.
Place in the fridge for a minimum of 2 hours, but ideally overnight. Trust me, the longer you leave it, the better it will be. If you can, take it out of the fridge periodically to spoon more marinade on top of the pork.
Preheat your oven to 200c. Take your marinated pork fillet out of the dish and place into a new oven-proof dish. Spoon more marinade on top and dispose of any leftover marinade.
Place in the oven for 10 minutes at 200c, then turn it down to 170c for the remaining 20-25 minutes.
Remove it from the oven. If you have a digital cooking thermometer, the internal temperature of the pork should be 65c. The best way of checking if it's cooked otherwise is to just cut it in half. If there's no pink in the middle then it's done.
Serve it up in Singapore noodles, chopped up in stir fries or fried rice. Enjoy!