Roll out the dough and slice into triangles.
Spread the frangipane cream on top of each triangle, leaving a 1cm border clean around the edge. Be careful not to overfill otherwise the frangipane cream will leak out in the waffle maker. I'd suggest using 1-2 teaspoons per croffle.
Starting from the base of the triangle, tightly roll the dough up tucking the triangle point underneath.
Use your fingers to pinch the dough at both ends to seal them off.
Pour the caster sugar onto a plate, then roll the croissants in the sugar so they are lightly coated.