Fire up your barbecue ready for two zone grilling, so you can cook directly and indirectly. Simply light charcoal on one side of your barbecue (using a chimney starter if possible) and leave the other side of the grill fire-free. This gives you heat flexibility and instantly puts you more in control of the fire.
Begin with the romesco sauce. Brush a little oil over the red peppers and set onto the grill bars directly over the fire. Grill for around 20 minutes, rotating regularly until they are soft and lightly charred. Move slightly off the heat if they are charring too quickly, you are not looking to blacken them. Remove from the heat, allow to cool for a few minutes then slice in half and remove the seeds and stem. Set aside.
Meanwhile, toast the almonds in a dry frying pan over a medium heat for a few minutes until they are golden. You can do this on the barbecue by setting the pan slightly off the fire, or on the hob inside. Tip into a food processor and pulse until ground. Drizzle the rest of the oil over the slice of bread and grill for a couple of minutes to toast. Roughly chop and add to the food processor, along with the cooked peppers, garlic and smoked paprika. Blitz until smooth, adding just enough cold water to make a smooth paste. Season with a little vinegar to taste and salt and black pepper, then set aside at room temperature.
Make sure your grill is really good and hot, adding a little charcoal to the fire if necessary. Brush the rump tail all over with a little olive oil and season with plenty of salt. Place on the grill bars directly over the fire, cooking for around 15 minutes and turning regularly so it gets a nice crust all over. Using a meat probe, check the temperature of the meat at the thickest point. For rare steak, you want to get it off the grill at 45°C, for medium rare, take it off at 50°C. Then wrap in foil, set on a plate and rest for a good 10-15 minutes. The temperature will rise by 5-8°C on resting, bringing it up to a perfect eating temperature.
Whilst the steak is resting, drizzle a little more oil over the spring onions and season with a little salt and pepper. Cook over a hot barbecue for about 10 minutes, turning occasionally, until cooked and nicely charred in places, then push to one side away from the fire to keep warm. Brush a little oil over the bread, set over the fire and grill both sides until lightly toasted.
To serve, divide the spring onions between the toast. Cut the steak across the grain into 1cm thick slices and pile on top. Spoon a little romesco onto the steak, sprinkle with the parsley and drizzle a little more oil over everything. Tuck in straight away.
