1 1/2 teaspoons kosher salt
1 teaspoon paprika
1 teaspoon pepper
1 teaspoon garlic powder
1/2 teaspoon dried thyme
1/2 teaspoon dried sage
1/4 teaspoon cayenne pepper
2 (6- to 8-ounce) boneless, skinless chicken breasts, trimmed and halved crosswise
1 1/2 cups all-purpose flour
1 teaspoon baking powder
3 tablespoons water
2 large egg whites, lightly beaten
2 quarts peanut or vegetable oil
4 potato sandwich rolls