Maltesers are made in two stages. The inner crunchy part is made of a mixture of malted milk (yes, Horlicks), skimmed milk powder, and salt. Once mixed they are made into little pellets. These pellets are then cooked in a vacuum oven which gives them their "honeycomb" texture (the low pressure cooking forces the bubbles in the mixture to expand, making the pellets larger). The now expanded pellets are then coated with chocolate. This is done by atomising the chocolate and spraying it onto the honeycomb as the balls blow through a vortex of air. Each little droplet of chocolate dries almost immediately so you get the even coating.