One way is a gratin: steam or boil cauliflower florets until just tender. Make a bechamel (or white) sauce, beginning with a roux of equal parts’ butter and flour (for a small amount, a tablespoon of each). Melt this together over low heat to bubbling, and then add hot milk a little at a time until you have a thick but pourable sauce, and season to taste. Pour over cauliflower to cover. Over the top, grate gruyere (or parmesan) cheese, and place under broiler until golden-brown.
The other way is a soup: take the stems of the cauliflower you used for the gratin, and simmer them in whole milk with a bay leaf and a clove of peeled garlic until tender. Remove the bay leaf, place all other solids in a processor or blender. Add a little of the cooking milk at a time and process as you go until you reach the desired consistency. Grate a bit of nutmeg into soup and season to taste. Toast some sliced almonds to garnish.
Truc (Tip): You can do this with other vegetables, such as broccoli, turnips, or parsnips.