*NOTE: For best results and to save money buy sesame seeds at a natural food store in bulk bins or at Asian markets where sesame seeds are sold in larger packages. This is a much less expensive way to purchase the seeds than buying sesame seeds sold in small spice bottle sizes. Also, keep sesame seeds in tightly covered container if not preparing tahini soon as they can go rancid quickly.
In clean, dry, large skilllet on low-medium to medium heat lightly toast the sesame seeds. Stir constantly being sure that seeds do not burn. Remove skillet and turn down heat if sesame seeds start to smoke. Toast for about 6-8 minutes then set seeds aside to cool completely. You'll know the seeds are done when they have a subtle fragrance.
Set seeds aside to cool slightly.
In blender fitted with steel blade or in a food processor, blend cooled seeds in two or three batches adding approximately 2 tablespoons of oil for each batch. Cover blender or processor and blend sesame seeds and oil. If appliance labors, add more oil, a little bit at a time.
The tahini should have the consistency of thick nut butter and will be very oily. There will be some whole sesame seeds that wil not blend, which is okay.
Scrap down sides of appliance frequently so that seeds blend well. Continue in same way for each batch of sesame seeds.
Transfer tahini to airtight container and refrigerate up to three months.
Yield is estimated.