Peel the bananas and halve them horizontally. Spear each half on a popsicle stick or straw and lay flat on a baking sheet. Freeze for at least 5 hours.
Finely chop the almonds and coconut. Toast them together for 10 minutes in a dry pan over medium heat, stirring constantly, until golden brown.
Melt the chocolate in a shallow heatproof bowl over boili