Royale With Cheese. But let's not start sucking each other's cocks quite yet.
in german "pfund" has been adapted to mean 0.5kg and remains in use as a colloquial term for that to this day. so you can keep calling it a quarter pounder.
a quarter pound is pretty dang close to a tenth of a kilogram (0.113 kg, to be more precise). We have a little-used prefix for that: A 'hectogram'.