Celery Gratin

Ingredients

• 1/2 cup butter, divided
• 6 tablespoons all-purpose flour
• 1 cup 2% milk
• 1 cup heavy whipping cream
• 3/4 cup shredded Swiss cheese
• 1/2 teaspoon salt
• 1/2 teaspoon pepper
• Dash ground nutmeg
• 8 celery ribs, cut into 1-inch pieces
• 1/2 cup chopped celery leaves
• 6 slices white bread, crusts removed