Black and white tahini cookies

Start by making the filling as it needs a little longer to chill. Put the chocolate, cream and cardamom, if using, into a small bowl and either melt in a microwave in small bursts, or put the bowl over a small pan of simmering water and heat, stirring occasionally, until melted and smooth. Once you have a smooth ganache, cover the bowl and chill until needed.

For the cookie dough, put the flours, cocoa powder, baking powder, bicarbonate of soda and salt into a large bowl, and whisk until everything is evenly distributed. Put the butter, tahini and sugars into the bowl of a stand mixer (or an electric hand mixer will also work well) and cream together on a medium-high speed for 1 minute until just combined. You are not trying to cream the mixture like a cake, just making sure everything is evenly combined and the mixture is smooth. Add the eggs, one at a time, and mix briefly until just combined. Add the vanilla and mix in briefly.

Add the flour mixture and mix on a slow speed until a uniform cookie dough is formed. Scrape into a bowl, cover and chill for at least 4 hours.

About 20 minutes before you want to bake the cookies, heat the oven to 180C/ fan 160C/gas 4 and line two baking trays with baking paper or silicone baking mats. Take the ganache from the fridge and divide into 12 equal pieces. Roll into balls and then press into 8cm-wide discs the width of a £1 coin. Put these onto the baking-paper-lined trays and freeze for 20 minutes.

Divide the cookie dough into 12 even-sized pieces and press into flat discs. It's important that the thickness is even and is only wide enough to be wrapped around the ganache. If the dough becomes too thin you risk the ganache escaping as the cookie bakes (don’t worry if this happens, the cookie will still be delicious). When forming the cookies I find it useful to take the ganache out of the freezer one piece at a time to prevent it softening.

Once all the cookies are formed, roll in the sesame seeds and put on the baking trays, setting no more than six per tray as they will spread. Bake for 12-14 minutes or until the edges feel set but the middles are still soft.

Remove and cool for 20 minutes before transferring to a wire rack to cool completely.

These cookies will keep in a sealed container for two to three days.