In a small saucepan, bring the water just to a boil. Add the chicken bouillon and stir. Set aside.

In a separate saucepan, heat the chicken fat over medium heat. When the fat has melted, whisk in the flour, onion powder, and black pepper. Cook, stirring often, for about 15 minutes, until the mixture takes on a brown hue that resembles milk chocolate.

While stirring, pour the bouillon water into the pan in a slow, steady stream. The gravy will thicken quickly, so stir continuously to avoid any clumps. Add the browning sauce if desired and cook, stirring occasionally, for 1 to 2 minutes, until the gravy thickens.

Remove the gravy from the heat. Stir in the butter and MSG, if using. Season with salt to taste.