Step 1

Preheat the oven to 450 degrees F. Grease a large baking dish with butter and add the broccoli and cauliflower. Roast until slightly browned, about 15 minutes.

Step 2

In a medium saucepan, melt the butter, whisk in the flour and let it cook over medium heat for 3 minutes. Turn the heat off, whisk in the half-and-half, then turn the heat up to high and keep whisking to avoid the flour from clumping. Add the Cheddar, salt and pepper and whisk until the cheese is melted.

Step 3

Remove the broccoli and cauliflower from the oven and pour the Cheddar mixture over the top. Sprinkle evenly with the breadcrumbs and bake until golden brown, 25 to 30 minutes.