Cavatelli are small, ear-shaped pasta. This dish is more of an American invention than a classic Italian dish, but it's delicious just the same. ADD THE LEMON JUICE to the mushrooms and mix well. Melt the butter in a skillet; add the garlic and Marsala. Cook for 3 minutes, then add the mushrooms. Cook for 5 minutes more. Add the whipping cream and bring the mixture to a boil. Add some salt, then pepper liberally. Remove from the heat. Cook the cavatelli al dente. Drain the pasta and return it to the pan in which it was cooked. Add the broccoli and the mushroom mixture to the pasta. Put the pasta mixture onto individual serving plates and top each with grated Parmesan.