The mushroom pie thread brought back a memory of the Tap & Growler brewpub in the late 80's (a couple of blocks west of Halsted/GreekTown). They had a great dish called Growler Pie which was a bed of creamy mushrooms, cabbage and IIRC leeks with grilled salmon on top and a pastry lid laid loosely over the whole thing. The vegetables were cooked in a cream sauce (not bechamel). Would love to find a recipe.