Good tahini is made from one ingredient: sesame seeds. If you have the time and are willing to put in the effort, you can make your own tahini simply by letting a ton of sesame seeds whip in a blender with some olive oil until you have a smooth paste. I get it though, sometimes you just need something to work in a pinch so in that case, substituting the tahini with cashew butter or almond butter would be your next best bet.