1/2 cube of unsalted butter
1 1/4C milk
1C freshly grated Parmigiano
1 1/2C pink oyster mushrooms
1lb Tacconi pasta (or lasagne*, or pappardelle)
Make a classic bechamel sauce with butter, flour and milk, melting the butter first, adding the flour, letting it "cook" in the butter and then adding milk. After it thickens, set it aside.
I used half the butter in this bechamel (1/4 cube). Sprinkle on a few grates of fresh nutmeg if you wish, although I did not do that, it seems like it would make a fine addition.
After separating the mushroom stems from on another and cutting off the tough bottoms, saute the mushrooms over low heat in the remaining butter. The color does fade so the mushrooms need only to be heated to soften them up. Add them to the bechamel.
Simmer the mushrooms in the bechamel sauce and add the grated cheese. Stir until the cheese melts completely. Drain the cooked pasta and place it in the pan with the sauce to incorporate it completely and even distribute the sauce and mushrooms with the pasta. Plate the pasta and sprinkle with fresh chopped parsley to add a contrast to the delicate color of the mushrooms. As you can see, they do retain a pale pink color.
*Lasagne pasta in the U.S. with the fluted edges may be as close to Tacconi as you can find here, so break them into 4 or 5 pieces (you may have better luck parboiling them, then cutting so they don't split). Any wide flat pasta will work.