Cut the onions in julienne and sauté them in a saucepan or frying pan with a dash of olive oil over a very low heat until they start to caramelize on their own, the onions must have a nice golden tone, then add a couple of spoonfuls of sugar and confit 10 minutes more.
In the meantime, the anchovies are washed by removing the head, intestines and the central spine and the anchovies are left to rest for half an hour in a container with water, a handful of salt and ice to wash the blood from them.
On a work table, the open anchovies are placed, on each one a spoonful of Torta del Casar is placed and it is covered with another open anchovy forming a «sandwich». Pass the anchovies through flour and beaten egg and fry for one minute on each side, remove on absorbent kitchen paper and reserve.
On a slice of crispy bread serve a teaspoon of caramelized onion, serve on top a anchovy stuffed with Torta del Casar.