Step 1

Preheat oven to 375°F. Spray a 9 x 13-inch Pyrex baking dish with nonstick cooking spray.

Step 2

Cook the cauliflower florets in a large pot of boiling water for 5 minutes. Drain.

Step 3

In a medium saucepan over medium heat, melt 3 tablespoons of butter. Stir in the flour. Continuing stirring to create a paste and cook for two minutes.

Step 4

Slowly pour in the half and half while whisking the entire time. Whisk in the salt and pepper. Bring mixture to a gentle boil and continue whisking for 1 minute, or until the mixture thickens up.

Step 5

Remove saucepan from the heat and stir in the extra sharp cheddar and 1/2 cup grated parmesan. Stir until smooth and cheese is melted.

Step 6

Remove about one cup of the cheese sauce and spoon it into the bottom of the prepared baking dish. Add cauliflower florets to the baking dish and pour the remaining cheese sauce over the cauliflower.

Step 7

In a small bowl, stir together Panko bread crumbs, remaining 1/4 cup grated parmesan cheese and 2 tablespoons melted butter. Sprinkle this mixture over the top of the cauliflower.

Step 8

Bake in preheated oven for 30-35 minutes, or until the topping is golden brown. Serve warm.