To make the marinade, place all ingredients into the Thermomix bowl. Blend 10 sec/speed 8. Scrape bowl and repeat.
Place pork (or beef) fillet in a bowl with the marinade. Stir to combine. Refrigerate for at least 4 hours. Remove from fridge 30 minutes before cooking.
Pour EVOO into a wok over medium-high heat. Add onion, spring onion and chilli. Cook, stirring until onion is transparent and starting to brown. Add Leekchi and cook until the liquid has almost all evaporated. Set aside.
Add pork to the pan, cook until browned. Add the onion and Leek-chi mixture and cook stirring until pork is cooked through.
Serve with a sprinkling of sesame seeds, and garnished with sliced spring onions. Serve with lettuce leaves and steamed rice.