An almond croissant is a variant of the traditional French croissant, filled with almond cream, or frangipane. They are made by baking a normal laminated dough croissant, which is then filled with the almond mixture, and rebaked; this process often uses slightly stale croissants.
Almond slivers and powdered sugar are commonly added on top for both flavor and decoration. The almond croissant was likely developed as a way to repurpose unsold croissants, and it has since become a popular pastry in bakeries worldwide.