Rayu

Rayu (辣油 _ja. "raayu") — sometimes transliterated as “ra yu”, “ra-yu”, “layu”, “la yu”, or “la-yu” — is chili-infused vegetable oil, used in Japanese cuisine as a cooking ingredient or as a condiment. The oil is typically sesame oil and the chili pepper used is typically red, imparting a reddish tint to the oil. Other ingredients used may include soy oil, corn oil, dried aloe, ginger, guava leaves, leek leaves, paprika, and turmeric.

One recipe

*sesame oil, 0.1 L (3.4 fl oz)
*red chili powder, 20 g (0.7 oz)
*ginger, 1 thick slice
*green leek leaves, from one plant

Mix all ingredients; boil and keep on fire for some minutes; allow to stand for one night; filter. (As a safety measure, a double-boiler should be used to boil the oil.)