This section is from the book "The Epicurean", by Charles Ranhofer. Also available from Amazon: The Epicurean, a Complete Treatise of Analytical and Practical Studies on the Culinary Art.
Scale and dress two Buffalo fish; raise the fillets without removing the skin; season and dip them in flour. Melt some butter in a pan pouring off the top while hot, put the fish into the pan, and fry very slowly, turning the pieces over when done; drain and dress them on a dish; put some melted butter into that already in the pan, cook it to hazelnut butter (No. 567) and take it from the hot fire; pour in a spoonful of cooked vinegar and a pinch of chopped parsley and chives, pour this butter over the fried fillets and serve.
Cut off the head and thin parts of the tails from three Buffalo fish; scale, drain, suppress the gills, wash and dry, raise the fillets and lay them in a buttered sautoir, moistening with a white wine mirepoix stock (No. 419), and let cook for fifteen to twenty minutes; drain off the fish and strain the stock. Prepare a good bechamel with cream (No. 411) and add to it a part of the strained fish broth; strain the whole and put it on to reduce, incorporating gradually into it some mushroom broth and fresh cream. Pour this sauce over the fish fillets and let them simmer in it for fifteen minutes on a very slow fire. Dress the fish and pour over a cream sauce (No. 404).
 
Continue to: