Bring a pan of water to a simmer over a low heat. Put the chocolate in a heatproof bowl and sit it on top of the pan, making sure that the water doesn’t touch the bottom of the bowl, and gently melt the chocolate.
Push a lollipop or cake pop stick into each marshmallow. Check the chocolate is melted completely by giving it a stir, then scrape it into a smaller bowl. Tip the white sprinkles into another small bowl. Put a wire rack next to the bowl of chocolate and a sheet of baking parchment next to the bowl of sprinkles.
Holding the end of a stick, dip a marshmallow into the chocolate so that it is completely coated. Lift it out, but hold it over the bowl to allow the extra chocolate to drip back in, then put it on the wire rack. Dunk the marshmallows, one by one, then line them up on the wire rack in the order that you dunked them.
Pick up the first marshmallow you dunked and dip into the sprinkles to completely coat. Sit the snowball marshmallow on the baking parchment. Continue to dip and coat the marshmallows, working along the line so that you cover them in sprinkles in the same order that you dunked them in chocolate. When all the marshmallows are covered, leave them on the baking parchment until they are set.
You can now wrap the marshmallows in cellophane and tie with ribbons if you’re giving them as a present. Alternatively, if you want to enjoy them right away, warm 1 mug of milk – in a microwave or saucepan – per snowball. Use your snowball as a stirrer in each mug of milk and keep stirring until all the sprinkles, chocolate and most of the marshmallow have melted. Check the milk is not too hot, then drink up. Will keep for up to 2 weeks in cellophane bags.