Mix saffron and water together and set aside for 15 minutes.
Combine harissa, mayonnaise, and the saffron mixture in a bowl.
Heat oil in a small pan and fry breadcrumbs until golden and crisp.
Stir chopped parsley into the cooled breadcrumbs.
Boil clams for 5-10 seconds until shells open and drain immediately.
Simmer 200ml oil, garlic, and chilli in a saucepan for 10 minutes.
Clean clams by removing the brown sack, dark tips, and gills.
Cut clam meat diagonally and return to half shells in an ovenproof dish.
Preheat the grill to a high setting.
Pour the warm garlic oil over the clams.
Grill clams 12cm from the heat for 2-3 minutes.
Top with breadcrumbs and serve with the prepared mayonnaise.