Preheat the oven to 180°C and toast the almonds and buckwheat together on a baking tray for ten minutes.
I like to pop my own popcorn, however you don't need much for this recipe. Perhaps pop a larger quantity to eat fresh and reserve 1/3 cup for the gravel road.
While the almonds and buckwheat are roasting, melt the chocolate in a double boiler on the stove. (I use a pyrex bowl which rests over, but doesn't touch the saucepan of boiling water).
Pulse the popcorn, roasted buckwheat and almonds briefly in a food processor, so that it has a coarse 'gravel' texture.
Stir the gravel mix with a pinch of salt into the melted chocolate, then pour it into a lamington tin, lined with baking paper. Smooth it out evenly with a spatula and set it aside until it's set (about an hour, depending on the room temperature).
Once the chocolate has set, break it into pieces and store it an in airtight container. The gravel road will keep for a couple of weeks .