There's a difference between tahini (sesame paste sold in jars) and tahini sauce (a mixture of tahini, lemon, and garlic). The paste is a great base note for sweet and savory dishes; the sauce is a stand-alone condiment worth drizzling over soups, sandwiches, and much more. Tahini sauce is also essential for great hummus (see box). We follow the Michael Solomonov method of steeping the garlic in lemon juice to remove its bite and let the tahini shine through. To turn it into a salad dressing, simply thin with a little water (about 1 tablespoon per 1/2 cup sauce).
Combine first 3 ingredients in a bowl; let stand 10 minutes. Add tahini to garlic mixture, stirring with a whisk to combine (mixture will be very thick). Add 6 tablespoons ice water, 2 tablespoons at a time, stirring after each addition until incorporated and sauce reaches desired consistency.