Dry fry the breadcrumbs in a medium frying pan for a few minutes until golden. Remove from the pan and set aside.
In the same pan, heat 1 tablespoon of the oil and add the chopped leeks. Cook for 10 minutes, until soft.
Meanwhile, whisk together the remaining oil, balsamic vinegar, honey and mustard in a small bowl.
Spoon the leeks into a serving dish and sprinkle over the Greek-style cheese, the breadcrumbs and then the dressing. Scatter over the lemon zest and serve.