1. In a saucepan combine butter and flour over low heat and do not let it get brown.
2. Add milk to the roux in the pan and keep stirring with a whisk in order to avoid lumps.
3. Season the sauce with salt, pepper, bay leaf and nutmeg
4. Cut the cauliflower into small florets and boil along with green peas.
5. Add the vegetables in the sauce and mix using a wooden spoon.
6. Put it in an oven proof tray and add a layer of grated cheese on top.
7. Bake till the cheese layer gets crispy and golden.
8. Drizzle with olive oil and serve.