We don’t use bain-maries or fancy chocolate melting dishes to avoid getting water or steam into the melting chocolate. Water/steam is death to chocolate and will make it seize up so always be super careful to avoid any excessive moisture getting anywhere near the pan when you’re melting chocolate or making ganache. We use a heavy-bottomed pan placed over the lowest possible temperature on the hob, and we keep stirring once the chocolate starts to melt. Remove the pan from the heat just before the chocolate is fully melted and continue to stir until it is smooth and glossy. If you overheat the chocolate (you’ll know because it will lack shine and stick heavily to the pan), you can add a small handful of grated chocolate and stir it in off the heat. This should stop the chocolate from getting that strange white coating when it sets.