Bloom the yeast with 75ml of cold water for 10m.
Combine flour with yeast water and 5g of sugar and use a KitchenAid to form a dough. If forming by hand, manipulate for 10 minutes.
Leave to rest covered with a kitchen towel for 1.5hrs at room temperature.
Heat a medium-sized pot of water on a stove over a high heat. Place a steamer over the top making sure not to touch the water.
Steam the carabineros for 1 minute each and immediately place into iced water to cool.
Combine the vinegar and remaining water with 45g of caster sugar and bring to a boil in a pot. Once boiling pour over the samphire and leave to cool.
Take the dough and roll into long cylindrical shapes. Cut the pieces into short 5cm strips. Cut parchment paper and place parchment onto the base of each circle of dough.
Place dough and parchment into the steamer with the heat off. Leave to prove for 25 minutes so the dough rises.
Once risen, turn to a medium heat and cook the dough for 12 minutes then remove from the basket and set aside.
Remove the head from the carabinero and squeeze juice into a small pot.
Deshell, retain the shells and slice thinly and reserve.
Drizzle olive oil over the head juices and add to a small pan. Heat over a medium temperature for 2 minutes stirring constantly. Season with salt and a touch of cracked black pepper.
Season the sliced carabinero with the head sauce, slice the bun in half from the top, add samphire and carabinero and serve warm.