To devein raw king prawns, cut off the head and peel away the shells and legs leaving the tail intact. With a sharp knife, cut along the top of each prawn and pull out the black vein. Wash and dry well. Place some salted water in a saucepan, bring to the boil and cook the prawns during 2 minutes or until the turn lightly pink.
Cut the Spanish green asparagus in 2.5cm/1in pieces discarding the tough end. Cook the Spanish asparagus in boiling salted water during 5 minutes. Drain the asparagus and cool them down in icy water.
Place the egg, saffron, lemon juice, salt and pepper in a blender or food processor. Process until blended, about 10 seconds. While the machine is running, pour in both oils in a thin, steady stream, until the mixture emulsifies and becomes thick and glossy. Add the chopped chives.
To make the brochette, thread a piece of asparagus, one prawn and another piece of asparagus on to each skewer. Serve along with the sauce.
Preparation: Sonia Fuentes/©ICEX.