Rinse the cauliflower florets and drain well.
Whisk together the starch, flour, salt and pepper. Add two to three tablespoons of ice-cold water to make a paste. Not too thick but just thick enough to coat the cauliflower florets.
Heat the cooking oil in a wok or frying pan.
Dump the cauliflower florets in the starch-flour paste and mix to coat each floret thoroughly.
Fry the cauliflower florets until lightly golden and crisp, about three to four minutes. Scoop out and move to a plate.
Pour off the oil from the pan.
Reheat the pan.
Dilute the miso paste in 1/4 cup of hot water. Pour into the hot pan and cook for a minute or two until bubbly. Turn off the heat. Stir in the sesame seed oil.
Add the cauliflower florets to the sauce and toss well.
Transfer the glazed cauliflower to a plate. Optionally garnish with sesame seeds and scallions before serving.