Prepare pastry and set aside.. Crumble sausage in a medium skillet; add onion and garlic. Cook over medium heat until sausage is browned, stirring occasionally; drain well.. Thaw spinach, drain well. Remove remaining moisture by pressing spinach between layers of paper towels. Add spinach to sausage mixture; mix well.. Sprinkle cheese evenly in pastry shell. Top with sausage mixture. . In a medium mixing bowl, combine eggs, cream and salt; mix well. Pour egg mixture over sausage mixture.. Bake in a 375 degree oven for 45 minutes or until a knife inserted halfway between center and outer edge comes out clean. Let stand for 10 minutes before serving. Garnish with cherry tomatoes and watercress if desired.