Béchamel

White roux and milk, infused with onion and bay. The gentlest of the five and the one everything creamy is built on.

• 25 g — butter
• 25 g — plain flour
• 500 ml — whole milk
• 40 g — onion
• 1 pc — clove
• 1 pc — bay leaf
• 1 pinch — nutmeg, grated
• 4 g — salt
• 1 pinch — white pepper

50 g roux : 500 ml milk

1. Warm the milk with the onion, clove and bay until it just steams. Take it off the heat and leave it to infuse while you make the roux.
2. Melt the butter over a low flame, stir in the flour and cook for two minutes, stirring the whole time. It should foam and smell faintly of biscuit but take no colour at all — this is a white roux.
3. Take the pan off the heat and let the roux settle for a minute. Pour in a third of the hot milk and whisk hard until it is completely smooth before adding the next third. Cold roux and hot milk is the combination that never lumps.
4. Return the onion and bay to the pan and set it over the lowest heat you have. Cook for twenty minutes, stirring across the bottom every few minutes so nothing catches. The sauce should barely move.
5. Strain through a fine sieve, then season with salt, white pepper and nutmeg. Press a piece of buttered paper onto the surface if it has to wait — a skin is easier to prevent than to fix.

Gratins, croque-monsieur, lasagne, endive in ham, anything that wants a quiet creamy body. Grate Gruyère into it and you have Mornay.