BAKE pastry shells at 350°F for 8 to 10 minutes or until lightly browned. Remove from oven; cool slightly.
MEANWHILE, mix salad dressing and flour in large bowl with wire whisk until well blended. Add eggs and milk; mix well. Add cheese, spinach, bacon and tomatoes; mix well.
POUR 2-1/2 cups of the filling into each shell.
BAKE at 350°F for 35 to 45 minutes or until filling is set in center and crusts are golden brown.