Preheat the oven to 350°F. Line 2 baking sheets with parchment paper.
Using an electric mixer fitted with the paddle attachment, beat together tahini, sugar, egg, baking soda and salt until well combined.
Dampen your hands with water to prevent sticking and roll tablespoons of dough into balls. Place on the prepared baking sheets, spacing cookies about 2 inches apart. Flatten each cookie slightly with the back of a spoon. Sprinkle with sesame seeds. Bake until cookies are golden on the bottom but still soft in the center, about 12 minutes.
Let cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack and let cool completely. Cookies will keep in an airtight container at room temperature for up to 5 days or in the freezer for up to 2 weeks.
Note: We've provided special diet and nutritional information for educational purposes. But remember — we're cooks, not doctors! You should follow the advice of your health-care provider. And since product formulations change, check product labels for the most recent ingredient information. See our Terms of Service.