The product is called Mämmi, or Memma in Swedish. It's made out of rye flour and malt, takes about 6-7h to make, and it's eaten with milk, cream and sugar. I've never made it myself but obviously you can't find it anywhere outside Finland so I went for it and was surprised at how easy it was. I had a hard time even finding ingredients, but thanks to the great guys at Dan's Homebrewing Supplies I got lots of good stuff to tinker with and the result was surprising. It was, against all odds and my cautious expectations, a great success, super yummy, and really makes Easter feel like Easter, even far away from all my own folks and traditions. The recipe is a mix of Finnish and Swedish ones I dug out from the internet, adapted to suit the ingredients I found.
Ingredients (serves 8 if they're all crazy about it, 15 if they just eat it because it's Easter)
8 dl rye flour
3 dl roasted malted barley*
3,5 dl malt extract*
1 tbsp ground bitter orange peel*
peel of 1/2 orange peel (fresh, grated)
1 dl molasses
2 tbsp brown sugar
Heat the water to about 60oC (this is according to the recipes but I actually used water that I'd just boiled - worked fine) and pour it into a large bowl. Add the barley and the rye flour and let stand, covered, in the oven for 3h at a fairly low temperature (my oven doesn't do lower than 70oC so i turned it off a couple of times because you don't want it to start simmering). You can use the stove too on the lowest setting, in that case just give it a stir every now and then. The mixture will be quite watery at the start but get a bit thicker in the oven - not much thicker than pancake batter though, don't worry if it seems a bit thin.
Take the bowl out of the oven and raise the temperature to 150oC. Add all the other ingredients and stir until they are well mixed. Transfer the batter into an ovenproof dish (I used a rectangular oven pan about 15x30cm) and put it back in the oven. It now stays in the oven for another 3h, but you need to stir it every 15-20min to ensure that it gets evenly baked. A film will form on top of the batter and this needs to be mixed back in every now and then, hence the stirring. When it's done the consistency should be like treacle ("like proper treacle", my British husband adds, "like the kind that a spoon will stand up in"). After the 3h are up, or when the consistency is right, take the mämmi out and let it cool down. It will have become even thicker now it's cooled down, like mudcake. Serve the mämmi with milk and a bit of cream (or just cream, I guess, I think some people eat it just with cream, others just with milk) and some white sugar. Enjoy your Finnish Easter!
* Some notes on the ingredients: After lots of searching, I finally found the malted barley, malt extract and bitter orange peel in a homebrewing supply store. I don't know how important the roasted malted barley is in the recipe because in the end all the malty taste came from the extract. The barley did provide the right colour, though. It came in whole pearls but they ground it for me in the store, as fine as they could but it was still much coarser than flour. As for the bitter orange peel, it's an important part of the taste, but before I stumbled upon it in the beer brewing store I had planned to use fresh orange and lemon peel and a splash of angostura bitters, to get that slight bitter tinge that bitter oranges have. I might try that anyway next time as it took me like half an hour to grind the bitter orange peel with pestle and mortar - it was like trying to grind stone!