Romesco has a long history and a host of traditions. The word for this sauce is Mozarabic in origin, and its reputation has become firmly rooted throughout the Catalan geography, even spreading beyond its frontiers. Each house prepares its own romesco sauce and each romesco is different. It is basically a sauce which goes perfectly with a fish like cod, but also with shellfish, rabbit, snails, pork or roast vegetables. It can also be used as a kind of roux if water or fish stock is added, followed by a few medallions of gurnard, rockfish or monkfish, for example. Ingredients such as hot and mild ground chilli pepper, parsley, flour when it is cooked in casseroles and suquets (fish stews), white wine, brandy and biscuits, among others, give rise to different types of romesco.
Blanch the romescu peppers and remove the flesh.
Roast the garlic bulb and when cool, place six or seven cloves in a mortar and pound to a paste. Gradually add the almonds and hazelnuts to make a paste. Add a pinch of salt, a little vinegar and a slice of bread fried in oil.
When the paste is very fine, add the flesh of the peppers and then slowly add the oil. Stir to bind as though you were making a mayonnaise.