Tahini is a paste made from sesame seeds and is popular in many Eastern and Mediterranean dishes. It can be purchased from most health food stores or you can simply doing the following-
Measure out 2 cups of sesame seeds and spread them out onto a baking tray. Place into a pre heated oven at 200 degrees Celsius for 4-5 minutes. DO NOT let them brown. You just want to dry them out a bit.
Transfer them to a blender or a food processor and add 1/4 cup of olive oil and blend until you have a nice smooth paste. Makes about 2 cups worth.
Store in a airtight container in the refrigerator.