Rouille is a classic French garlic mayonnaise with Cayenne Pepper. The word "rouille" actually describes the "rust" or red colour of the sauce. Saffron gives the dish its distinctively Provencal taste & also adds a subtle depth to the sauce. Rouille is traditionally served as an accompaniment for the spicy seafood stew "Bouillabaisse or any other French fish soups. It is easy to make and can be stored for up to a week in the fridge. I LOVE the earthy smell of the saffron in this garlic mayonnaise — it gives the sauce a heady aroma that stands up to the pungency of the garlic and the heat of the cayenne pepper.......great spread on toast too!! NB: Rouille is often made with bread and mashed potatoes - depending on the French region - this recipe is for a lighter version, and has no bread or potatoes added.