Bouquet garni and oignon clouté

Two ways of adding flavour you intend to take back out. Both exist so the sauce never has to be strained twice.

1. Bouquet garni: thyme, bay and parsley stalks tied inside a split leek leaf, or in a loop of string tied to the pot handle so you can pull it out without fishing.
2. Oignon clouté: half an onion with a bay leaf pinned to it by two cloves. Used in Béchamel and in white stocks, where loose aromatics would have to be strained out later.
3. Take both out after forty minutes. Herbs left in a stock for hours stop giving flavour and start giving bitterness, especially bay.