Place the rice, milk, water, condensed milk and sugar and bring to a gentle boil over low heat, stirring to mix everything.
Reduce heat and simmer for 30 minutes, stirring from time to time, especially at the end, to prevent burning.
At 30 minutes, add the coffee, stir and cook for a couple more minutes, just to let the additional liquid dry up a little.
Take off heat and add the chocolate pieces, butter and vanilla, stirring until the chocolate is completely melted and the consistency seizes up slightly from the chocolate (thickens).
Notes
Serve in little dessert dishes or shaped as I have done in the picture above. Of course, if you are a fan of mini desserts as I am, tiny little shot glasses not only make a great presentation but will also make the recipe go further!