Step 1

Adjust the oven rack to the middle position, pre-heat the oven to 350ºF (180ºC) and line two large baking sheets with baking/greaseproof paper.

Step 2

In a large bowl, using a wooden spoon, mix together the tahini paste, softened butter, light brown soft sugar and vanilla bean paste until combined. Don’t cream the butter mixture – just stir it all together until smooth and all ingredients are well combined.Tip: You don't want to cream the tahini, butter and sugar together, as that aerates the mixture (that is, it incorporates air into it), which can cause the cookies to spread too much in the oven.

Step 3

Sift together the gluten free flour blend, cornstarch, xanthan gum and salt, and add them to the butter mixture. Mix well with a wooden spoon until the dough starts coming together, then knead it by hand until smooth. The dough shouldn’t be sticky to the touch.

Step 4

Chill the dough in the fridge for for 15-30 minutes. This will firm it up, which makes it easier to shape it into logs.

Step 5

Divide the dough into two equal portions and shape each into a log about 7 inches (18cm) in length and about 2 inches (5cm) in diameter.

Step 6

Mix the white and black sesame seeds together and sprinkle them in an even layer on a large plate or platter. Roll each cookie dough log in the sesame seed mix, then wrap them tightly in cling film or baking paper, and chill in the fridge for about 2 hours or until solid.

Step 7

Using a sharp serrated knife, slice the logs into about ½ inch (1cm) thick cookies and place them onto the lined baking sheets. Space them out slightly, leaving about ¾ inch/2cm of space between them.You should get about 16 cookies per log, 32 in total.

Step 8

One baking sheet at a time, bake at 350ºF (180ºC) for about 12 minutes until light golden brown. While one baking sheet is in the oven, keep the other one in the fridge.

Step 9

Immediately out of the oven while they’re still very hot, you can correct the shape of the cookies using a round cookie cutter slightly larger than the cookie diameter. Use the cookie cutter to nudge the cookies into a more round shape if necessary.

Step 10

Allow the cookies to cool on the baking sheet for about 5-10 minutes, then transfer to a wire cooling rack to cool completely.

Step 11

Storage: The cookies keep well in an airtight container in a cool dry place for about 2-3 weeks.