In a saucepan, melt the butter. Add the flour, stir and cook for 1 minute. Stir in the milk and bring to a boil, whisking constantly. Simmer gently for a few minutes. Season with salt and pepper.
In a pot of boiling salted water, cook the pasta al dente. Drain and oil lightly. Set aside.
In a large skillet, sauté the mushrooms in the butter over high heat until they lose their moisture and turn golden brown. Season with salt and pepper. Add the green onions and garlic. Continue cooking for about 2 minutes. Add the pasta and heat through. Deglaze with the vodka and flambé, if desired. Add the béchamel and tomatoes and mix thoroughly. Adjust the seasoning.
Serve in a large bowl. Sprinkle with the Parmesan cheese, green onions and pine nuts.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.