To make the chorizo mixture, heat the extra virgin olive oil in a large non-stick frying pan over a medium heat. Add the onion, garlic and peppers with the 1 tsp of salt. Cook, stirring, for 8 to 10 minutes until the vegetables have softened. Add the chorizo and cook, stirring, for 8 to 10 minutes until it releases its fat. Add the tomato puree and paprika, stir for 2 minutes, then add the tomatoes and cook, simmering, for 15 minutes until thickened and reduced. Season to taste.

For the cheese sauce, put the butter in a saucepan over a low to medium heat and stir until melted. Add the flour, garlic powder, onion granules and cayenne and cook for 2 minutes. Add the milk in 2 batches, whisking to to make sure there are no lumps. Whisk in the sour cream. Turn the heat up to medium and bring to a simmer. Cook for 5 minutes or until slightly thickened. Remove from the heat and stir in half the cheese and season, to taste.