Use whatever seafood you have - make sustainable choices, please! For this b'stilla I used Pink Shrimp (wild-caught, from Oregon), Bay Scallops (farmed), Mussels (farmed), Pacific Cod (longline-caught, from Alaska), Squid, and Shrimp.
Saute onions, garlic, mushrooms with the seafood, except the shrimp. Season with lemon juice, salt, pepper, paprika, and cumin. When seafood is almost cooked, add fresh, rough-chopped taragon.
Layer six sheets of phyllo dough is a large sauce pan. Fill the dish with the seafood mixture, drained of its sauce. Fold the overhanging pastry towards the middle and cover with a second layer of filling. Cover with the remaining pastry sheets and form a seam by folding the pastry over the edges and tucking inside the rim of the dish. Seal the seam with egg yolk. Overturn the pie onto a flat baking dish. Brush with melted butter. Bake at 400 degrees till the phyllo dough is browned and crisp, probably about 35 minutes.
In the meantime, marinate large shrimp in the cooking liquid. Pour off the liquid and quickly brown the shrimp. Lay a layer of thinly sliced lemons on the cooked pie and pile on the shrimp.
This is the dish that received the loudest ooos and ahhhhhs. Brian said it succinctly: "two of my favorite things - seafood and pie!"