Heat a skillet or pan and add a enough of the cooking oil to grease the pan.
Make sure the skillet is very hot and the oil is evenly coating the surface of the skillet. I usually pour excess oil out and keep it for the next pancake.
Check the consistency of your starter, it should have the runny, smooth consistency of pancake batter. It it's not hydrated enough, add your dashi or stock little by little until the discard has a smooth runny texture. If your discard is already very hydrated, don't add more liquid.
If using, chop the chives and or spring onions finely and set aside.
Pour the discard into the heated skillet slowly until the liquid has filled the surface of the cooking surface. Try to make this layer as thin as possible. This will cut down the cooking time of your pancake significantly and make it more crispy.
If using, sprinkle the sesame seeds evenly onto the batter you just poured into the pan. The batter should still be uncooked, and the sesame seeds should sink into the uncooked surface of the batter slightly.
If using, quickly sprinkle the chives and spring onions onto the pancake as well.
Let the pancake cook for a few minutes over medium heat. The thinner your pancake, the quicker it will be done and ready for flipping. After a minute you should notice little holes forming on the surface of the batter. Turn down the heat a little to make sure you don't burn one side while the middle is still cooking.