Mix the flour and salt. Keep aside.

Beat the butter and sugar until light and fluffy, roughly about 4-5 minutes.

Add egg yolks and vanilla extract and beat well after each addition.

Add the flour to the above mixture in three iterations. Mix well after each.

Separate half of the cookie dough and add the liquid food colouring.

Take walnut sized dough from each dough and separately roll into even length ropes over a lightly floured surface. Place them together and press lightly. Make a spiral from the resulting rope. Roll one end to make a cane. If the dough is soft, keep in the fridge for about 15 mins to harden.

Place the cookie dough on parchment paper covered baking sheet and bake in a preheated oven (175 degrees) for about 8-10 mins.