Preheat oven to 375°F. Butter 13x9x2-inch glass baking dish. Saute sausage in medium nonstick skillet over medium heat until brown and cooked through, breaking up with back of fork into small pieces, about 10 minutes. Add shallots and garlic and saute 3 minutes. Add sun-dried tomatoes and 2 tablespoons parsley; stir 1 minute. Spread sausage mixture in prepared dish. (Can be made 1 day ahead. Cover and refrigerate.) Whisk eggs, egg yolks, half and half, whipping cream, 1 1/2 cups cheese, and salt in large bowl to blend well. Pour egg mixture over sausage mixture in dish. Sprinkle remaining 1/2 cup cheese and 2 tablespoons parsley over. Bake until top of casserole is golden brown and knife inserted into center comes out clean, about 30 minutes. Let stand 5 minutes before serving.