sole fillet stuffed with a mushroom duxelle; a sauce and parmesan polenta

because murphy's laws run rampant in my life, i haven't had a chance to post lately. we did eat in the meantime. the child was fed. for the most part. (do hot-dogs count?)
anyhoo, my meat-and-potatoes husband raved about this dish. we really loved it, and we're not that big on fish. we like shrimp and scallops, but fish, eh. this i'll make again and again.

i don't know how to accurately describe the cooking method - it's not a roast/bake/broil, though it's in the oven. oven-poach. i think that's a reasonable description. it's poached/steamed in dry wine, and the flavour is unbelievable.
this is what you need:
6 to 8 sole fillets
8 oz/225 gr wild mushrooms, i used a blend of shiitake, oyster and crimini
1 onion
1 tb chopped parsley
1 tb butter
1 tb flour
1 cup/250 ml milk
1/2 cup/125 ml dry white wine (or apple cider)
2 ts lemon juice
zest of half lemon
pinch nutmeg
1/2 ts garlic powder
for the creamy polenta:
2 cups/500 ml chicken broth
6 tb instant polenta
1/3 cup grated parmesan
salt, pepper

chop the onion and sweat it in a bit of olive oil over medium heat while you finely chop the mushrooms. add  them to the pan and cook until all the juices are evaporated, about 15 minutes. (you can do this in advance.) mix in the parsley and take it off the heat.
preheat the oven to 350F or 180C. meanwhile, wash and dry the fish. salt and pepper the fillets. these you want about 1 1/2 inch wide, so split in half lenghtwise if needed. reserve 2-3 tb of the mushrooms and equally divide the rest between the fish. spread all over the fillets, pressing gently to make it adhere, on the skin side if skin was not removed. roll up the fish, tail to head end, and put it in a baking dish as closely together as possible. pour the wine over it. cut a piece of parchment to fit the dish and cover all the fish. butter it and place it directly on the fish, so the butter sticks to the fillets. bake for about 20 minutes. depending on your oven, check after 15.
to make the polenta, bring the stock to boil. decrease to a gentle simmer and slowly stream in the polenta. slowly. slowly. or you'll have lumps. stir for 5 minutes. add the parmesan. kill the heat. stir and taste for salt and pepper. keep warm.
when the fish is nearly ready, heat the remaining mushrooms in 1 tb butter. when it's melted add the flour and stir to blend. cook for a couple of minutes then stream in the milk, whisking continuously. add garlic powder and nutmeg. cook on low heat for about 5 minutes. now take the fish from the oven and strain 4 tb of the cooking juices in the mushroom sauce. add the lemon juice and zest, taste for salt. let it sit on very low heat while you plate the polenta and the fish. spoon sauce on top. take a bite and be surprised.

recipe adapted from here.