For either the plain or the chocolate glaze, combine the margarine or butter with the powdered sugar in a medium bowl and blend with an electric mixer.
Add the vanilla and hot water. Mix until smooth.
If you're making the chocolate glaze, melt the chocolate chips in a microwave-safe bowl in the microwave for 30 to 40 seconds. Stir, then microwave another 30 seconds and stir again until completely melted. Add to the plain glaze mixture. Blend until smooth.
When the donuts have cooled, dip each \top surface into the glaze and then flip over and cool on a plate until the glaze firms up, about 15 minutes.