>>18250991 cup moka coffee maker from bialetti (moka express 1 cup), if you have room and can spare 300 grams.
You can reduce weight by removing the plastic bits (which will melt anyway on open fire) and removing the lid.
Use a bandana to grab it from the fire and avoid splashing by using the bottom of your cup as a cover. Use the top or bottom chamber as a stash for ground coffee.