Heat the oil in a medium-sized saucepan. Add the onion and cook on low-medium for 5 mins - until the onion is soft. Give it a stir every minute or so.
1 tbsp. vegetable oil, 1 red onion
Add in the ginger and garlic and cook for a further minute. Add in the rest of the ingredients, turn up the heat, and bring to a gentle bubble.
1 thumb-sized piece of ginger, 4 cloves garlic, 600 g (21 oz) ripe plums, 6 tbsp. dark soy sauce, 4 tbsp. honey, 1 tbsp. Chinese rice vinegar, 4 tbsp. sriracha
Turn the heat back down to medium and allow everything to bubble gently for 20 minutes. Give it a stir every so often.
After 20 minutes, turn off the heat and blend the mixture in the pan using a hand blender. I like to give it just a few pulses so the sauce still has some texture.
Notes
Prep ahead: You can allow the sauce to cool and then cover and refrigerate for up to a week. Reheat in a pan before serving..Nutritional Information is per cup.