Cauliflower Gratin

Preheat oven to 375°F. Coat a 7-by-11-inch (2-quart) baking dish with cooking spray.

Bring 1 inch of water to boil in a large pot fitted with a steamer basket. Add cauliflower to the basket, cover and steam until just tender, about 6 minutes. Remove the cauliflower from the pot; set aside. Wipe out the pot.

Add 1 1/2 cups milk to the pot; bring to a low boil over medium-high heat. Whisk flour into the remaining 1/2 cup milk; gradually add the mixture to the boiling milk. Cook, whisking constantly, until slightly thickened, about 1 minute. Reduce heat to low and whisk in garlic powder and pepper. Add cream cheese and 3/4 cup Parmesan, whisking until the cheese is melted and the mixture is smooth. Remove from heat. Gently stir the cauliflower into the cheese mixture; transfer to the prepared baking dish.

Combine panko, parsley, oil, salt and the remaining 1/4 cup Parmesan in a small bowl; sprinkle evenly over the cauliflower mixture. Bake until the mixture is bubbly and the topping is crispy and golden brown, about 20 minutes. Let stand for 5 minutes before serving.