Prepare the Miso Glaze: In a small bowl, whisk together the white miso paste, maple syrup, soy sauce, and rice vinegar until smooth. If you're using them, stir in the minced garlic and grated ginger. Set the sauce aside for later.

Wash and Dry the Beans: Rinse your trimmed green beans under cold water. This next step is crucial: pat them completely dry with a clean tea towel or paper towels. Any moisture on the surface will prevent them from charring properly.

Heat the Pan: Place a large frying pan or skillet over a medium-high heat. Add both the toasted sesame oil and the vegetable oil. Let the oils heat up for a minute until they shimmer slightly.

Blister the Green Beans: Carefully add the dry green beans to the hot pan, spreading them into a single layer. Let them cook undisturbed for 3-4 minutes. You want them to develop dark, blistered spots on one side. Avoid the temptation to stir them too early.

Continue Cooking: After the initial sear, toss the beans and continue to cook for another 4-5 minutes, stirring occasionally, until they are tender-crisp and charred in places.

Add the Glaze: Turn the heat down to low. Pour the prepared miso glaze over the green beans in the pan.

Toss to Coat: Immediately begin tossing the beans continuously to coat them evenly in the sauce. The glaze will thicken very quickly. What works best for me is to keep everything moving constantly for about 60-90 seconds until the sauce is glossy and clings to every bean.

Serve Immediately: As soon as the beans are coated, remove the pan from the heat. Transfer the Miso Green Beans to a serving platter.

Garnish and Enjoy: Sprinkle generously with toasted sesame seeds and finely sliced spring onions before serving warm.