Dark Chocolate Peanut Butter Cups

The filling needs to be stiff enough to sit as a disc, not spread — that is what keeps the chocolate seal unbroken.

Aim for a thin base and a thin lid; a thick shell overwhelms the center.

Powdered sugar is doing structural work here, not just sweetening — it stiffens the filling enough to hold its shape against warm chocolate.

Freeze the filling discs first and the assembly stops being fiddly.