Put the sesame seeds in a large frying pan set over a medium heat to gently toast for a few minutes, stirring as they begin to turn light brown. They will clump a little. Remove from the heat and stir again to break them up.

Tip the seeds into a high-speed blender and add the oil. Blend for around 5-8 mins until the tahini becomes as smooth as you can get it. Season with sea salt, if you like. Will keep chilled in a sterilised, airtight jar for up to two weeks.