Wash cauliflower and cut it into florets. Add them with ½ tsp salt into a pot, top with water, and bring to a boil. Let it cook for 5 minutes, then drain over a sieve. → Don't forget to set ¼ cup of the cooking water aside for the sauce.
Arrange cooked cauliflower in a casserole.
Béchamel Sauce: Melt oil in a saucepan over medium heat. Add flour and stir constantly for 1 minute.
Pour in dairy-free milk and cauliflower cooking water, bring to a boil while whisking constantly. Reduce heat and let it simmer for approximately 5 minutes until thickened.
Season with salt, pepper, and nutmeg.
Pour the béchamel sauce over the cauliflower, then sprinkle the grated cheese on top.
Bake for 20-25 minutes in the preheated oven.
Notes
Vegan: Use a dairy-free cheese alternative or omit cheese altogether.Keeps fresh for 3 days. Store leftovers directly in the baking dish (e.g. covered with cling film - easiest to reheat) or in an airtight container in the refrigerator.Reheat for 20 minutes in the oven, preheated to 390°F (200°C).