Add the yeast, sugar and warm water to a small bowl and mix. Set aside for 10-15 mins or until foamy. To a large mixing bowl, add the flour and salt, then add the yeast mixture, kimchi liquid and gochujang. Mix with a spatula until a wet dough forms, lifting and pressing the dough against the sides of the bowl for about 5 minutes. Add in 30ml of the chilli oil and use your hands to squeeze this into the dough until combined. Add a bit of the remaining chilli oil to a clean bowl and add your dough to the bowl. Cover and rest for 30 minutes, then using your hands fold the dough over itself 4 times, turning 90 degrees after each fold. Rest for another 30 minutes then repeat the folds. Rest for a further 30 minutes then do a last set of folds.

Add some chilli oil to a lined 8 inch/20cm square baking tin and place dough into the tin. Stretch the dough out to fill the whole tin using the back of your fingers/knuckles. Cover the tin and proof dough until it is puffy and jiggly (about 1-1.5 hours).

Preheat oven to 220C. When the dough has proved, use oiled fingers to create dimples in the dough - pressing down to the bottom of the tin. Mix kim chi with spring onions and scatter over the top of the dough, finishing with some sesame seeds, flakey salt and the remaining chilli oil. Bake on a lower rack in the oven for 25-30 minutes or until golden brown (the kimchi will char - don't worry you want this!). Remove focaccia from tin, cool on rack and then slice and serve!