This recipe was created when my four-year-old daughter asked to make peanut butter cups and I had to tell her we were out of peanut butter. She said, That's ok, let's just use speculoos spread! Brilliant. Speculoos cookies are a traditional cookie common here in Belgium, as well as Holland and Germany. You can find them in America with a bit of searching. Trader Joe's® and Amazon sell both speculoos cookies and spread (which they call cookie butter).
If you like things to have a bit of crunch, do not crush the cookies as finely as you might otherwise.
You can use whatever chocolate is your personal favorite!