Preheat oven to 400F. Line a square baking pan with foil and prepare another piece of foil to use as a cover.

Wash the leeks well and cut them into slices about half an inch thick. This doesn't need to be too precise! You will have what seems like a lot of leeks - layer them in the pan very snugly since they will shrink as they cook.

In a bowl, mix together milk, a generous pinch of salt and lots of black pepper. Pour over the leeks.

Sprinkle blue cheese evenly on top of the leek mixture, followed by the dukkah and the breadcrumbs.

Cover with foil and bake covered until fork tender, about 1 hour and 30 minutes. Uncover and bake for 15 more minutes for a bit of color and extra crunch.