Preheat oven to 450 F. Melt butter in medium saucepan on medium-high heat. Add onion; cook and stir 5 minutes or until tender. Add flour, Gravy Mixes, sage and garlic powder; stir with wire whisk until well mixed. Gradually stir in broth and half-and-half until well blended. Bring to boil. Reduce heat to low; simmer 5 minutes or until slightly thickened, stirring occasionally.
Stir in turkey and mixed vegetables; simmer 5 minutes or until heated through, stirring occasionally.
Meanwhile, unroll pie crusts. Cut out 3 large circles from each crust. Place on baking sheet. Bake 8 to 10 minutes or until golden brown. To serve soup, ladle into soup bowls and top each with 1 crust.