Melt 200g plain chocolate and 50g butter in a large bowl over a pan of simmering water.
Stir in 1 can (397g) of condensed milk and remove from the heat.
Allow to cool, then mix in 225g self raising flour.
Chill in fridge for 10 minutes or so.
Place large teaspoonfuls on a baking tray. Leave plenty of space to allow them to spread.
Press 2 or 3 chocolate buttons (stolen from children's lingering Easter chocolate stash) into each cookie.
Bake at 180 degrees for 15 minutes; the cookies will still be quite soft but will harden up when cooled.