This broccoli and cauliflower au gratin is cheesy vegetable perfection. It's easy enough for a weeknight, but delicious enough for the holidays and it's always gobbled up.
Preheat oven to 350 degrees. Butter the bottom and sides of a 9x13 baking dish with one tablespoon of butter.
Add the broccoli and cauliflower to the buttered dish and drizzle with the oil. Season with salt and pepper.
Bake for 20 minutes, stirring once halfway through.
Start the cheese sauce when the vegetables have 8 minutes left to bake.
To make the cheese sauce
To make the cheese sauce, melt the butter in a medium sauce pan.
Add the garlic to the melted butter and cook, stirring constantly, for 1 minute.
Whisk in the flour, salt, and pepper. Cook for 1 minute.
Slowly add the milk to the flour mixture, whisking constantly. Cook, whisking constantly, for 4-5 minutes or until mixture reaches the consistency of a thin gravy.
Remove from the heat and whisk in the cheese until the sauce is smooth and creamy.
To bake
Remove the vegetables from the oven and stir. Pour the cheese sauce evenly over the vegetables.
Combine the Panko and melted butter and sprinkle over the dish.
Return to the oven for 10 minutes.
Place the pan under the broiler and broil until the bread crumbs are browned, about 2 minutes, if desired.
Remove from the oven, sprinkle with parsley, and serve.
Notes
We prefer fresh vegetables in this dish, but frozen will likely work.You may swap out the Havarti for shredded cheddar, if you prefer.