How to do it:

• Place the unpeeled garlic cloves in a blender or small food processor. Add the lemon juice and 1/4 teaspoon of salt. Blend on high until the garlic is coarsely puréed.
• Let the mixture stand for 10 minutes to let the garlic mellow. Pour the lemon and garlic mixture through a fine mesh strainer set over a medium mixing bowl, pressing the solids to extract as much liquid as possible. Discard the solids. This step helps to make the tahini sauce silky smooth and keeps it from tasting too strongly of garlic.
• Add the tahini to the strained lemon juice in the bowl, along with the cumin and remaining 1/4 teaspoon salt.
• Whisk to combine. As you can see below, the mixture will be very thick.
• Add ice cold water a few tablespoons at a time, whisking constantly, to thin it out. The sauce will lighten in color and seize up as you whisk.
• When the tahini seizes up or tightens, keep adding the water, bit by bit (about 1/2 cup total), until the sauce is smooth, creamy, and thick.
• Taste and adjust seasoning with more salt and cumin, if necessary. If you’re not using the sauce immediately, whisk in a few tablespoons of ice-cold water to loosen it up before refrigerating (it thickens up quite a bit in the fridge). The tahini sauce can be refrigerated for up to a week, or frozen for up to a month.