Preheat oven to 350° F. Grease a 1½-quart round casserole; set aside.

Cook pasta to al dente, according to package directions. Rinse with cold water to stop the cooking; drain well. Return pasta to saucepan, then add apples.

Melt butter in medium saucepan. Add onion and cook over medium heat for 3 minutes. Stir in flour; cook and stir for 1 minute, or until fragrant.

Slowly stir in milk with wire whisk. Bring mixture to a gentle simmer, stirring constantly. Add bay leaf. Reduce heat to low, and cook sauce for 10 minutes, stirring often.

Remove and discard bay leaf. Stir in 2 cups of the cheese and dry sherry. Cook and stir about 1 minute or until cheese is melted. Remove from heat; season to taste with salt and pepper.

Add cheese sauce to pasta-apple mixture; gently stir until well combined. Transfer to prepared casserole. Sprinkle with remaining ⅓ cup cheese and panko. Bake, uncovered, at 350° F for 30 minutes, or just until heated through and lightly browned. Stand about 5 minutes before serving.

Source: U.S. Apple Association