Preheat the oven to 180°C/Gas Mark 4 and line two baking trays with Lakeland Magic Non-Stick Liner.
In a large bowl, mix the butter and caster sugar until light and fluffy. Beat in the egg yolk and vanilla extract. Sieve the flour into the bowl and add enough milk to make a soft dough. Bring the mixture together with your hands, then lightly knead until smooth. Wrap in clingfilm and chill for at least 15 minutes.
On a lightly floured surface, roll out the dough to 5mm (1⁄4in)thick. Cut out 10 circles with a 9cm (31⁄2in) cookie cutter. Place on the baking trays and bake for 18 minutes or until golden. Set aside for 10 minutes, then transfer the biscuits to a wire rack to cool completely.
On a surface lightly dusted with icing sugar, roll out the white icing to 3mm (1/8in) thick. Cut out 10 circles with a 10cm (4in) cookie cutter. Spread 1⁄2 tsp jam in the centre of each biscuit, leaving a 1cm (1⁄2in) gap around the edge. Place a marshmallow on top of each biscuit, slightly off-centre.
Using your thumb and index finger, soften the edge of each icing circle to create the melted effect. Place the icing onto each biscuit and smooth it over the marshmallow with your hands.
To decorate the snowmen, firstly make 12 little scarves using the coloured icing of your choice from the Primary Colours Icing Pack. On a surface lightly dusted with icing sugar, roll out the icing to 3mm (1/8in) thick, then cut out curvy scarf shapes with a sharp knife. Stick the scarves to the snowmen with a dab of boiled, cooled water. Next, mould coloured icing into 12 little hats and stick on with more water. Make 12 carrot noses by blending small amounts of red and yellow icing to make orange.
Complete the snowmen by drawing on buttons, twig arms, eyes and mouths using the Writing Icing pens. Let the icing set then place the biscuits into gift boxes or bags.