Toast sesame seeds over medium-low/medium heat, stirring constantly to cook evenly & prevent burning.
1.5 c raw sesame seeds (~8 oz) 1
When they're golden and have a lovely nutty fragrance (~5-10 min), remove from heat and let cool completely (I transfer to a bowl to cool in fridge because ~impatience~).
Add sesame seeds and toasted sesame oil to blender / food processor, and blend into a thick paste. Scrape down sides as needed. 2
3 tbsp toasted sesame oil
Store in airtight container in the fridge. 3
Notes
It's more common to find containers of "toasted sesame seeds" rather than raw, but i've found that some aren't toasted all that much – aka don't have as much of that nutty fragrance. If they're not a deep golden color, I'd recommend additional toasting until fragrant.
If you want a looser consistency, blend in more sesame oil, but note that sesame paste is usually mixed with other liquids (e.g., soy sauce, vinegar) that will thin it out whenever you use it.
Quality nut/seed butters should always be stored in the fridge after opening, as the oils are sensitive to going rancid. If the oil has separated and is sitting at the top, mix well to integrate before refrigerating.