Step 1

Preheat oven to 350˚F. Melt 2 tablespoons of the butter in a large skillet set over medium. Add cabbage, celery, onions, and garlic, and cook, stirring often, until tender, 10 to 15 minutes. Transfer to a 3-quart lightly greased (with cooking spray) baking dish.

Step 2

Melt 2 tablespoons of the butter in a medium saucepan over medium; whisk in flour, and cook, whisking constantly, until smooth and thick, about 1 minute. Gradually add milk to saucepan, whisking constantly to remove any clumps. Cook, whisking constantly, until thickened and smooth, about 3 minutes. Remove from heat, and whisk in Worcestershire, salt, pepper, and 1/2 cup of the Parmesan until smooth. Pour sauce over cabbage mixture.

Step 3

Place remaining 1 tablespoon butter in microwavable bowl, and microwave on HIGH until melted, about 30 seconds. Add breadcrumbs and remaining 1/2 cup Parmesan to melted butter, and stir until combined. Sprinkle breadcrumb mixture evenly over cabbage.

Step 4

Bake in preheated oven until casserole is bubbly and breadcrumbs are golden, 20 to 25 minutes.