Roughly cut 5 zucchini into 1-inch pieces. I like cutting the pieces on a bias by holding the knife at a 45° angle and rotating the zucchini as I chop. But you do you, babe! Pat dry with a clean dish towel to remove any moisture.
Heat a large pan on medium-high. Add 1/2 tbsp neutral oil and let it heat up. Just before the oil starts to smoke, add the cut zucchini and fry until browned on one side. Shake the pan to toss, lower heat to medium, and season with a small pinch of salt. Miso can be salty, so we don't want to over season the zucchini at this stage. Continue cooking until the zucchini are soft, about 10 minutes.
Make a hole in the centre of the pan, exposing the bottom. To the hole add 1 tbsp miso and 1/3 cup water. Using a wooden spoon or spatula, mix the miso into the water until it has dissolved. Toss to coat, then add in 3 tbsp butter and cook on medium, continuously stirring, until the butter has melted and the miso-water is slightly thickened. Once thickened, stir in 1 tbsp rice wine vinegar and 1/2 tsp honey. Taste and adjust seasoning.
Remove from heat and serve with sesame seeds.
