Preheat the oven to 350°F. Spray an 11x7-inch baking dish with non-stick cooking spray.
Into a large deep skillet over medium heat, add 2 tablespoons of butter. When the butter is melted, add the cabbage, celery, and onion. Cook, stirring frequently for about 10 minutes, until the cabbage is crisp-tender. Add the garlic and continue cooking for an additional 1 minute. Transfer the cabbage mixture to the prepared baking dish.
In a medium saucepan over medium heat, add 2 tablespoons of butter. When the butter is melted, whisk in the flour. Gradually pour in the evaporated milk, whisking constantly until smooth and slightly thickened, about 3 minutes.
Remove the saucepan from heat, then whisk in 1/2 cup Parmesan cheese, Worcestershire sauce, salt, and pepper. Pour the sauce evenly over the cabbage mixture.
Using a microwave, melt the remaining 1 tablespoon butter. Add the breadcrumbs and remaining Parmesan cheese. Stir until combined then sprinkle over the cabbage mixture.
Bake 25 minutes, until the casserole is bubbly and the breadcrumbs are lightly golden. Serve hot.