Drain and rinse the chiles. Cut them up one side, seed them and open them flat. Arrange chiles in a shallow baking dish lightly coated with vegetable cooking spray.
Cut the cheese and turkey into 1/2-inch strips. Fill each chile half with cheese and turkey strips. Fold over edges of chiles and place seam-side down in dish.
In a medium bowl, combine flour, baking powder and salt. In a small bowl, whisk the milk and eggs. Slowly add egg mixture to flour mixture, beating until smooth. Pour over prepared chiles.
Bake at 450° F for 15 minutes. Remove from oven and turn off heat. Sprinkle cheddar cheese over top and return to oven 1 minute to melt cheese.Servings: 6