>>697033Call that person a fucking retard, and make them go the store right now to buy some gravy.
If you still want to make your own, and you don't have any stock, drippings, or caned stuff, the best I can come up with is
* 1 teaspoon yeast extract spread, e.g. Marmite/Vegemite
* 1 teaspoon onion powder
* 1 teaspoon salt
* 1 1/2 cups hot water
* 4 tablespoons butter
* 1/2 cup cold water
* 2 tablespoons cornstarch
DIRECTIONS
1. Melt butter in a saucepan over medium heat. Stir in yeast extract spread, onion powder, and salt until smooth. Gradually whisk in 1 1/2 cups water so no lumps form. Bring to a boil. In a small cup, stir together 1/2 cup cold water and cornstarch. Stir the cornstarch mixture into the saucepan, and continue boiling until thickened. Cool slightly before serving.