Preheat the oven to 150°C and grease and line two large baking sheets.

Cream the 125 g butter and both sugars together until pale and creamy.

Add the eggs, one at a time, beating until combined.

Mix in the black gel food colouring to your preferred intensity.

Fold in the flour, cocoa, and baking powder until just combined.

Spoon teaspoonfuls of the mixture onto the baking sheets, sprinkle with black sesame seeds, flatten slightly, and bake for 15-20 minutes.

Cool on wire racks.

For the filling, beat the 60 g butter, tahini, milk, and icing sugar until light and fluffy. Add black food colouring as desired.

Pipe the filling onto half of the cookies and sandwich with the remaining halves.

Cut liquorice into strips and insert them as legs into each spider while the buttercream is still soft.