First, cut off the green stems from the chillies then cut each chilli in half lengthways. Thinly slice the chillies widthways then place into a large saucepan, along with the seeds.
Peel & grate the garlic & fresh ginger then add into the pan with the chillies.
Add the sugar, vinegar, water, honey, soy sauce, chilli flakes & paprika into the pan then set over a medium-low heat. Cook, stirring frequently until the sugar has dissolved. This will take 3-4 minutes.
Next, stir the Sambal Oelek into the sauce then turn the heat up to medium heat & bring the sauce to the boil. In the meantime, add the cornflour & water into a small bowl & stir to make into a smooth paste.
Once the sauce is boiling, stir in the cornflour slurry then cook for another 2-3 minutes, stirring pretty much constantly, until thick. The sauce should be thick enough to coat the back of a spoon.
Once cooked, take the pan off the heat & let the sauce cool. Then transfer the chilli sauce into a sterilised jar & store in the fridge.