few food colourings and writing icing pens, in your favourite colours
icing sugar, for rolling
Put the flour, butter, bicarb and sugar in a food processor, whizz until you can’t see any lumps of butter, then tip into a mixing bowl. Whisk the egg, syrup and vanilla together, then stir into the bowl with a wooden spoon. Using your hands, knead together into a smooth dough.
Heat oven to 200C/180C fan/gas 6. Cut a triangle template from card the size you want the bunting to be. Roll out dough on a lightly floured surface. Use template to cut out triangles - re-roll trimmings to get as many as you can. Line some baking sheets with baking parchment and lift on the biscuits. Use a pencil end to make 2 holes in the top of each one - not too close to the edge. Bake, one tray at a time, for 8-10 mins, remaking each hole when biscuits are just out and still soft. Cool. Un-iced biscuits can be frozen for up to 3 months, or will keep in an airtight container for a week.
Divide the icing into as many colours as you want, and knead in food colourings to get your desired colours. Roll out thinly on a surface lightly dusted with icing sugar, and use your template to cut out icing triangles. Brush the backs of the icing with a little water and stick onto the biscuits - making holes in the icing to match the biscuits as you go. Cut out small circles from leftover icing, brush backs with water and stick onto some of the biscuits. Decorate with icing pens, if you wish, then carefully thread through ribbon or string and hang up your treats.