Pour the milk into a non-stick pan and drop in the garlic and rosemary. Put it on the heat and bring it to a brisk simmer. Keep an eye out though, as, given the chance, the milk will boil over like invaders pouring over a castle wall. Make sure you regulate the heat accordingly. You want to reduce the milk by approximately two-thirds, down to 120ml. Ignore the unsightly milk-skin, old-spider-web look, as this will all become a beautiful creamy sauce; just push any skin down into the milk with a wooden spoon. The reducing process will take about 25-30 minutes.
Release the anchovies from their tin or jar and drop them into the food processor or blender bowl. If the anchovies are tadpole-sized, throw in a few more. Personally, I like the whole ones cured in chunky salt (wash and de-bone them first). Wash and peel the carrots and artichokes and destring the celery. Retaining the peeler, shave all the vegetables lengthways in ribbons into a large bowl of cold water clinking with ice-cubes. This will make them supercrisp. Squeeze in half the lemon juice, to stop the artichoke discolouring.
Deconstruct the Trevise lettuces. Having thrown away any damaged outer leaves, the Trevise, with its tight leaves, shouldnâ€™t need washing. Tear each leaf into about four pieces and throw them into a large mixing bowl. Do this one by one until the leaves become too small to carry on. Chuck the last ones in whole. Repeat with the other lettuce.
In a salad spinner, or by other means, dry the shaved vegetables very well. Add them to the lettuce. Finely crumble over a little chilli (some flakes would do), add a pinch of salt and squeeze over the other lemon half. Pour over 2 tablespoons good olive oil. Mix everything gently and thoroughly before dividing it evenly between the plates.
Remove the milk pan from the heat and take the rosemary stem out.
Pour the reduced milk, the rosemary leaves and softened garlic into the food processor or blender, all over the waiting anchovy fillets. Do not scrape the bottom of the milk pan, as any burnt â€˜catchingsâ€™ will not blend properly and the sauce, that should be really smooth, will become bitty. Turn the power on high and in a thin, thin stream start pouring in the olive oil. After a while you will begin to see the sauce thicken. It is easier to tell how thick your mixture has become by stopping the blades and seeing it settle. When it has reached the consistency of a yoghurt drink or loose mayonnaise, it is done. Remove the blades and flick 2 good tablespoons about each plate of salad. Eat your â€˜autumn slash winter saladâ€™ immediately.
LEFTOVERS: As the dressing chills it will thicken. It is delicious on hot bread and with strong dark meats such as roast beef and venison fillet, as well as next to a good crispy hunk of fish such as grey mullet.