Turning a flower into a pie

How do you turn this ....

...into this? (It's called un gratin in French.)

First you have to cut a cauliflower up into what are called florets. Put the florets (fleurettes in French) in a steamer pot and steam them over boiling water until they are just starting to get tender.

Arrange the florets in a baking pan. Add some meat if you want — pre-cooked chicken or pork lardons.

Make a sauce béchamel and turn it into a sauce mornay by melting some grated cheese in it. Pour the sauce over the florets and bake them in the oven until the top starts to brown (see above).