I have seen something similar in Scandinavian cookbooks (and purchased them at Ikea several years ago). Comparing to your recipe, rolled oats can be substituted with leftover cake crumbs. Coffee, rum, or orange juice can substituted for water. An flavorful extract may be used too. When made with rum, they are called "romkugler" in Danish, where bakeries sell them as a way to use leftover cake.
For an EYB recipe search, try searching "cocoa" in the recipe search box, and filtering by ethnicity/Scandinavia & by either recipe types/baking/candy, sweets or recipe types/baking/cakes, small.