Halva

In a medium bowl, have the room-temperature tahini and vanilla extract ready.

In a small saucepan, combine the sugar and water. Bring to a boil over medium-high heat. Attach a candy thermometer and boil without stirring until the syrup reaches exactly 240°F (115°C), the soft-ball stage.

Immediately remove the syrup from the heat and carefully, slowly pour it into the tahini while gently stirring with a wooden spoon.

Stir the mixture just until it begins to pull away from the sides of the bowl and takes on a dull, crystallized texture (do not over-mix, or the halva will become crumbly instead of flaky). Fold in the remaining pistachios.

Quickly press the warm mixture into the prepared loaf pan. Let it cool to room temperature, then refrigerate for at least 24 hours to cure before slicing.