Ingredients

• 2 garlic cloves, peeled
• 1 teaspoon kosher salt, plus more
• 1 bunch watercress, thick stems trimmed
• 1 cup fresh mint leaves
• 1/2 cup fresh flat-leaf parsley leaves
• 1/2 cup tahini (sesame seed paste)
• 2 tablespoons (or more) fresh lemon juice

Instructions

1. Cook garlic in a medium saucepan of boiling salted water until slightly softened, about 30 seconds. Using a slotted spoon, transfer garlic to a bowl of ice water; let cool.
2. Return water in saucepan to a boil. Cook watercress, mint, and parsley just until wilted, about 15 seconds; drain. Transfer watercress and herbs to ice water; let cool. Drain watercress, herbs, and garlic and squeeze between paper towels to remove as much moisture as possible; coarsely chop.
3. Purée watercress, herbs, garlic, tahini, lemon juice, 1 teaspoon salt, and 3/4 cup water in a blender until smooth, thinning with more water as needed to reach desired consistency; season with salt and more lemon juice, if desired.
4. DO AHEAD: Sauce can be made 3 days ahead. Cover and chill. Shake before using.