A Spoonful of Whiskey

 is a Fallout 3 quest that is added to the game with the Point Lookout add-on.

Walkthrough
She will try and convince you that she is sick, and she needs these items to get better. With Medicine and Speech she will admit she makes Moonshine and ask you to gather these items for caps as well as a share of the Moonshine.

You will need*
 * 3 Yeast
 * 6 Fission Batteries
 * Either 10 Refined Punga Fruits or 20 Wild Punga Fruits

You can also repair her still for caps

* It is a wise idea to keep light and find a way to get the fission batteries, and punga fruit to Margureit, carrying it altogether will come up to weigh a massive 70 lbs., or 80 if your carrying wild punga, if your also carrying the whole 12 lbs. of yeast, you might even end up carrying 82 or 92 lbs of ingredients

Reward
You will receive 300 caps and several Moonshine. You can also repair her still for an additional 100 caps (200 with a speech check).