I've been a bit hesitant writing this recipe, because the Swedish name for them is chokladbollar, which literally translates to chocolate balls... There are some connotations in English that makes that a less suitable name. But as I made them again today it struck me what they actually are: a sort of cheap and simple pralines. Lovable by kids and adults alike, and can be varied in a multitude of ways.
There are more detailed recipes somewhere out there, but I usually just do this by feel so I'll write down what I do and some ways one can vary them.
The ingredients are few:
I start off with about 50 grams of butter and cover it with cacao, add sugar and oatmeal. Then knead it all together in a bowl. In my experience you can often take less sugar, more cacao, and a lot more oatmeal than you might expect.
The butter softens as your hand(s) warms it up. Taste the dough. Is it sweet enough? Is it a good amount of cacao? Is it too sticky (add oatmeal in that case)? When it sticks together and you like the taste of it it's done.
Roll marbles the size of your thumbnail and put on a plate. Then let this plate rest in the fridge for a while (or put it in the freezer while you brew a pot of tea), to let the butter harden a bit again.
In short these are simple to make, can be varied endlessly, and are all around a nice treat.
-- CC0 Björn Wärmedal