First, you need to roast all the ingredients for the romesco. Preheat the oven to 170–180°C. Cut the garlic in half crossways and place it on a large piece of foil. Sprinkle with olive oil, salt and pepper and fold over the foil to close. Roast for 20 minutes, until very soft, then squeeze out all the cloves.
Put the almonds on a baking tray in a single layer and roast in the oven until light golden brown (around 6–7 minutes).
Remove the core from the tomatoes with a small knife, place on a roasting tray with a good drizzle of olive oil, salt and pepper, and roast for 8-10 minutes. The tomatoes will start to break down and lose their liquid and the juices will colour with the olive oil.
Put 1cm of oil into a pan on a medium heat and fry the bread until golden brown on both sides – it should be toasted and have absorbed all the oil.
Put the tomatoes (with their skins) into a blender with the garlic, chillies and choriceros, the 250ml of olive oil and the vinegar, and blend to make a dark, thick paste. Rip up the toasted bread and add along with salt, pepper and the almonds. Pulse to blend, so that it comes together but you keep some texture – if you want it to be creamier, keep blending. Keep it warm until you need it.
To cook the calçots, fire up your barbecue. As soon as you have flames, add the calçots and cook until the outside layer is blackened and burnt. Remove from the barbecue, wrap in newspaper and leave them to sit for 20 minutes – they will continue to steam, cooking inside the paper.
Unwrap, take a calçot and hold it by the green end, then pull the top two burnt layers down over its head and discard: you will be left with the soft, sweet interior. Dip this into the romesco, then dangle it down into your mouth and eat. Repeat!