Whisk together the miso, tamari, maple syrup, sesame oil and water in a small bowl until smooth.
Heat the olive oil in a large frying pan over a medium-high heat.
Add the mushrooms in a single layer and cook for 8-10 minutes, stirring occasionally, until they’ve released their moisture and become deeply golden with lightly caramelised edges.
Pour in the miso glaze and toss everything together for a further 2-3 minutes, allowing the sauce to bubble and coat the mushrooms until glossy and sticky.
Transfer to a serving bowl and finish with the sliced spring onions, toasted sesame seeds and a generous twist of black pepper.
Serve immediately as a side dish, or spoon over steamed rice with a side of wilted greens for a simple midweek meal.
