Mars Muffin

If you don’t have a muffin tin, double up the paper liners so they stand more stably.

Slightly chilled bars cut more cleanly and stick less to the knife.

Coating the pieces in flour helps prevent them from sinking while baking.

Buttermilk and egg at room temperature combine more evenly.

Do not overmix, otherwise the muffins may become firm instead of fluffy.

An ice cream scoop makes portioning quick and neat.

Check with a skewer near the end: it should come out almost clean; a few melted chocolate traces are fine.

Cooling on a rack prevents moisture buildup so the tops stay nicely dry.