2 cups cooked chicken, diced or shredded
1 tablespoon olive oil
1 onion, chopped
2 cloves garlic, minced
2 carrots, diced
2 celery stalks, diced
1 cup frozen peas
1/4 cup all-purpose flour
2 cups chicken broth
1/2 cup milk or cream
Salt and pepper to taste
Pastry dough for the crust (store-bought or homemade)