"Muisjes" or "little mice": sugarcoated anise seeds, usually white, pink or blue. Because the "tail" of the seed sometimes remains outside the sugarcoating, this resembles mice somewhat.
"Stomped little mice" ("gestampte muisjes"), smashed or grind down "muisjes" into a fine white sugary powder which is then put on bread.
"Mice droppings"; "muizenstrontjes" (in Flanders) or "hagelslag" (in the Netherlands), small pieces of chocolate put on bread.
Dutch / Flemish gruesome breakfast habits: eating "little mice", "stomped mice" , and "mice droppings" on bread or rusk...