Coat the oysters with katakuriko and then gently rinse with running water. Without using oil, place the oysters in a frying pan and lightly brown the surface.
Add the oyster sauce and the ra-yu to the frying pan from Step 1 and cook to coat the oysters with the flavor. Remove the oysters and let cool.
Place the oysters and the red chili pepper in a storage container. Fill with olive oil until completely covered. Let them marinate overnight and then enjoy whenever you want.
These will keep in the refrigerator for 6-7 days depending on the season. Check before eating.
If you aren't a fan of spicy foods, omit the chili pepper. You can use the extra oil for pasta or as a bread dip.
Story Behind this Recipe
I had these at an izakaya (Japanese pub) and really enjoyed them. The shop used white sesame oil to marinate their oysters but I always make mine with olive oil.
After adding the oyster sauce, lower the heat to low so that it doesn't burn. You can adjust the amount of ra-yu. There's the chance that the oil will harden while in the refrigerator, but if you leave it out at room temperature a bit before eating, it will be ok. When cooking the oysters in the beginning, make sure all the water is evaporated!