Brown Gravy

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

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.