Preheat oven to 450 degrees F. Press pie crust onto bottom and up side of 9-inch fluted tart pan with removable bottom; trim edge, reserving trimmings. Prick bottom of crust with fork. Bake 10-12 minutes or until golden brown. Cool. Reduce heat to 375 degrees F.
Cook sausage in large skillet over medium heat 4-5 minutes or until hot stirring frequently. Remove from skillet; set aside.
Melt butter in same skillet. Add mushrooms; cook 3 minutes or until tender, stirring occasionally. Place in large bowl. Add eggs, cheese, 1/2 cup cranberries, cream, parsley and sausage; mix well. Pour into tart shell.
Roll out reserved pie crust trimmings on lightly floured surface. Use cookie cutters to cut into decorative shapes; arrange over filling.
Bake 25-30 minutes or until knife inserted in center comes out clean. Top with onions and remaining cranberries. Cut into 8 wedges to serve.