1. Put all ingredients - except the cornstarch slurry - into a saucepan and bring to a rolling boil.
2. Reduce heat and let boil for 10 mins. or until it reduces by half.
3. Reduce the heat to low then add the cornstarch slurry and stir to incorporate until sauce thickens - approx 2 mins.
4. Remove from heat and taste.
5. Store at room temperature for service.

Please note:

You should taste sweet first, followed by sour, then spicy and salty notes. If the sauce isn't sweet enough, add a little more sugar. If it’s not as spicy add some more Togarashi.