Riisipuuro is basically rice cooked in milk, a kind of porridge (like a Finnish version of the Spanish arroz con leche), served warm with a sprinkle of sugar and cinnamon.
For the ones that do not plan to visit Helsinki any time soon, here is the Riisipuuro recipe to try it out at home:
2 tsp butter
2 dl rice
a bit of salt
Instructions1. Put the water and butter to boil.
2. Add milk and rice.
3. Mix well* until it starts to boil.
4. Turn down the heat and mix until the boiling stops.
5. Add salt to taste.
6. Remove from the heat and serve while it's still warm.
7. Sprinkle each plate with sugar and cinnamon.
*Remember to mix all the way to the bottom, so that the porridge does not burn.