Christmas cookies

Method

• step 1

  To make the cookies, mix together the flour, baking powder, bicarbonate of soda and ¹/2 tsp of salt. In a large bowl, beat together the butter, sugar and lemon zest for 5 minutes until light and fluffy. Whisk in the eggs, then briefly mix in the vanilla extract. Add the dry ingredients and the cranberries, and mix until a soft cookie dough is formed. Cover and chill for 2 hours or until firm.

• step 2

  Heat the oven to 180C/fan 160/gas 4. Cut the dough into golf-ball-sized pieces, roll into balls and put onto baking-paper-lined trays or use a silicone baking mat. Bake for 14-16 minutes or until lightly browned. Halfway through baking remove the trays from the oven and give them a firm tap on the surface to make the cookie collapse a little (this will give a chewier texture). Cool on the trays for 5 minutes before removing to a wire rack to cool completely.

• step 3

  For the buttercream, put the milk and pistachios in a pan over a medium heat and bring to a simmer. Remove from the heat, cover and leave to infuse for 1 hour. Pour the mixture into a jug and use a hand blender to purée until smooth (the nuts won’t fully break down but they’ll form a slightly pasty texture, almost like a milkshake). Pour the milk mixture back into the pan along with the flour, caster sugar and vanilla bean paste. Cook over a medium-high heat, whisking constantly, until the mixture is very thick, like a pastry cream. Scrape the custard into a small bowl and cover the surface. Chill for 2 hours.

• step 4

  To finish the buttercream, beat the butter until soft and creamy then add in the pistachio custard a spoonful or so at a time. Continue beating until a buttercream texture is formed. Depending on the colour of the pistachios you use you may want to add a drop or two of green food colouring – but be sparing. Put the buttercream into a piping bag fitted with a round nozzle and pipe a dollop of buttercream onto ¹/2 the cookies, sandwiching together with a second cookie. To finish, roll each cookie in chopped pistachios, coating the exposed buttercream.