Boil the milk in a heavy-bottomed pan, on a medium flame till it is reduced to half its original volume. Stir frequently to prevent the milk from sticking. When it is complete, cool the milk till it is just warm.
Put the sugar in another pan and heat it over a low flame to melt.
Allow the sugar to caramalise (brown). Remove from the fire when done, add the reduced milk to this caramalised sugar and mix well till it blend.
Mix milk and sugar thoroughly now add the yoghurt to the mixture and stir gently to mix.
Pour into the desired container and keep in a warm dark spot for the Mishti Doi to set. The best taste results are achieved by setting the Mishti Doi in a earthenware pot.
When the Mishti Doi has set and is firm, chill for a few hours and serve.