Break the milk chocolate into pieces and place it in a microwave safe bowl.
Melt the chocolate by cooking in the microwave for 30 second bursts, stirring between each one to ensure it melts evenly. Be careful not to overheat or burn the chocolate, heat only until just melted and smooth.
Drop spoonfuls of the chocolate into around half of the sections of your ice cube tray, dividing it equally between each section. The chocolate should fill each section to about two-thirds of the way up.
Repeat with the white chocolate - melting it in the microwave and spooning into the remaining sections of the mould.
Add a lolly stick to each section of the mould, pushing it right to the bottom of the chocolate to help it stay in place.
If using chocolate reindeer, unwrap each one and push it carefully into the chocolate next to each lolly stick.
Add mini marshmallows to top the remaining sections of chocolate.
Carefully place the tray in the fridge to chill. Make sure the cubes of chocolate are completely set before removing - chill for at least an hour or so to be sure.
Carefully pop the stirrers from the ice cube tray. Wrap up in cellophane to give as gifts. Make sure you include a label to explain what they are!
To serve, stir into a cup or mug of warm milk to turn it into delicious hot chocolate.