Crinkles

Chop the cranberries coarsely and soak them in rum. If you can do this a few hours in advance, do so.

Measure butter and chocolate into a double boiler and let them melt slowly. The slower, the better; in the meantime, you still have a lot to do, so don't burn the chocolate due to insufficient attention while stirring. Alternatively, you can melt it without a double boiler, but on the lowest heat setting and be ready to stir the chocolate a little bit at any moment.

Whisk eggs and granulated sugar into a thick, light foam that drips in streams from the whisk and briefly stays on the surface of the foam. Whisking with a stand mixer or hand mixer takes about 5 minutes, by hand at least twice as long.