Line two baking sheets with baking paper

Cream the butter and sugars together until light, soft and fluffy

Add in the chopped walnuts

Zest the orange directly into the bowl to avoid losing any of the essential oil, then mix the ingredients to distribute evenly

Add in the flour and egg, mix gently to form a dough

Once the mixture binds into a dough, remove from the bowl and shape into a tube

At this stage, you can choose to cut off half of the dough and freeze it to use later. Wrap the dough you intend using in cling film and put in the fridge for at least 2 hours to rest

Preheat the oven to 185c

Unwrap the dough and cut 'biscuit' discs to a maximum of 1-inch thickness

Lay the biscuits on the baking sheet with a gap in between to allow them to spread a little

Bake for 10-15 minutes, until the edges start to turn golden

Remove from the oven and cool on the tray for 5 minutes before transferring to a cooling rack

Store in an airtight tin