Dive into this creamy, cozy, roasted cauliflower gratin which is an easy make-ahead dish and a great alternative to potatoes.
- 1 cauliflower head, cut into florets
- 1 Tbsp extra virgin olive oil
- 2 Tbsp unsalted butter
- 1 small onion, diced
- 3 cloves garlic, minced
- 2 Tbsp AP flour
- 2 cups whole milk
- 3 sprigs rosemary
- 1/4 tsp nutmeg, grated (or ground)
- 3/4 cup parmesan cheese, grated + 1 Tbsp for topping
- kosher salt and pepper
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Preheat oven to 425 degrees F. Toss the cauliflower florets with 1 Tbsp olive oil and sprinkle with kosher salt.
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Arrange on a parchment lined sheet tray and roast until golden brown, about 30 mins. Reduce the oven to 375 degrees F.
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While the cauliflower roasts, make the sauce. Heat the butter in a large saucepan over medium heat. Add the diced onion and cook until translucent, about 5 mins.
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Add the garlic and cook 2 mins more. Sprinkle the flour over the onions and garlic and stir. Cook, while stirring, for 2 mins.
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Slowly pour in the milk while vigorously whisking. Add the rosemary sprigs and the nutmeg.
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Bring the milk mixture to a boil and reduce to a simmer, whisking occasionally to prevent it from sticking. Simmer for a minute or two until thickened and continue to whisk.
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Remove from the heat, remove the rosemary sprigs, and stir in 3/4 cup parmesan. Season to taste with kosher salt and pepper.
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Stir the roasted cauliflower into the sauce. Grease a 9 inch square baking dish and pour the cauliflower mixture into the dish. Sprinkle with 1 Tbsp parmesan and and bake until hot and bubbling, about 30 mins. Serve hot.
- Cut the cauliflower into similar sizes so it roasts evenly.
- When making the sauce, be sure to whisk frequently to prevent lumps and the sauce from sticking to the bottom of the pan.
- Making ahead? You can make this cauliflower gratin through the last step (just before baking) and refrigerate for up to 2 days. Allow an extra 5-10 minutes baking time if baking directly from the refrigerator.
- Don't skip roasting the cauliflower! Roasting helps to draw out the moisture from the cauliflower which prevents the gratin from becoming watery.