Râyu (ラー油), also written layu, is an aromatic oil in which chilli provides heat while sesame oil develops toasted notes. A few drops are generally enough to spice up a dish without masking its other flavours.
Râyu originated from Chinese chilli oils, which exist in many regional variations. It was later adapted in Japan, where its most common form is a fluid oil, often made with sesame oil infused with chilli. It is served especially with gyoza and Japanese dishes inspired by Chinese cuisine, which are particularly popular in restaurants and family cooking.
This classic Japanese râyu should be distinguished from chilli oils containing pieces of chilli, garlic, onion, nuts or seafood. These thicker preparations, sometimes known in Japan as taberu râyu (食べるラー油), are eaten together with their crispy ingredients.
They provide more texture and are almost condiments in their own right. Their composition and level of heat vary considerably from one recipe to another.
The most traditional use is to add a few drops of râyu to a sauce made with soy sauce and rice vinegar for Japanese dumplings; gyoza sauces also provide a quick way to prepare this dipping sauce. Râyu can also spice up the broth of ramen and chukamen, mabodofu, soups, stir-fried noodles or a simple bowl of rice.
It works particularly well with mild foods such as Japanese tofu, eggs, steamed vegetables or seasoned cucumber. Fluid oil can be measured drop by drop and added directly to the plate or towards the end of cooking to preserve its aroma. Crispy chilli oil is better added with a spoon, so that you can enjoy both the oil and its pieces.
It is best to begin with a small amount: depending on the chilli and the recipe, two râyu oils can have very different levels of heat.
