You will need a 28 cm (10 inch) tart or springform tin.
Preheat the oven to 160°C (320°F).
To make the base, combine the flour, butter, malted milk powder, sugar and salt in a food processor. Pulse only until crumbs are formed. Pour the crumbs into the tin. Shake from side to side and press very lightly with your fingers to make sure it is evenly spread.
Bake for 40 minutes until lightly browned. Remove from the oven and evenly scatter the chocolate buttons over the hot base.
Let it stand for about 5 minutes to melt and, using a spatula, spread the chocolate to cover the surface of the base.
Sprinkle the chocolate layer with the maltichocs.
Cool completely and cut into wedges to serve.