3 heads broccoli, cut into bite-sized florets
1 tablespoon olive oil
1 tablespoon butter
1 tablespoon flour
1 cup whole milk
1 pinch nutmeg
½ cup yellow cheddar cheese, grated
1/3 cup canned fried onions
salt and pepper
Preheat the oven to 425 degrees. Toss the broccoli florets with the olive oil and a pinch of salt. Arrange in one even layer on a rimmed baking sheet and roast for 20 minutes, until the edges of the broccoli are slightly charred.
Meanwhile, melt the butter over low heat in a saucepan. Add the flour and whisk to combine. Cook 1 minute, then drizzle in the milk bit by bit, whisking all the while. Bring to a simmer, and when the sauce has thickened, remove from the heat. Season with salt, pepper, and nutmeg, then add the grated cheese and whisk until fully melted.
Remove the broccoli from the oven and transfer to a casserole dish. Drizzle with cheese sauce and toss to combine. Top with fried onions and return to the oven for 5 additional minutes.