Cover a large oven tray with aluminium foil.
Using a scone cutter as a guide, mark 5cm circles on foil. I found the easiest way to do this was to temporarily place a double folded tea towel under the foil. That way it was easier to imprint than on a hard surface.
Meanwhile, pre-heat your oven to 180 Degrees C (350 F). Place almonds on a separate tray, and put into the oven for approximately 5 minutes or until golden brown. Stir the almonds once or twice to help them brown evenly.
Place sugar, water and butter into a medium sized saucepan, stir over low heat until the sugar has dissolved and the butter has melted.
Bring to a boil, boil uncovered about 25 minutes or until the mixture becomes a dark golden brown. Do not stir once the toffee comes to the boil.
Remove from the heat immediately, add the almonds all at once and stir just enough to combine. If you over-stir the mixture the sugar will crystallise.
Working quickly, place tablespoons of mixture on to circles, pressing out to the edge of the circles with the back of a spoon.
If the mixture becomes too thick, return the saucepan to the heat for a few seconds.
Place the chopped chocolate in a heatproof bowl.
Place the bowl on top of a saucepan which contains a small amount of barely simmering water.
Stir until the chocolate has melted; allow to slightly cool.
Turn the crisps over on to the flat side. Spoon some chocolate onto the flat side and spread out to the edge.
Allow chocolate to set - around 10 minutes.