If using freshly baked waffles that need time to rise, such as yeast-raised waffles, start the batter in advance of making the sauce.

For the sauce, combine the onion and 2 tablespoons of the margarine in a large saucepan. Sauté covered over medium heat for 5 minutes or until slightly browned, stirring once per minute to avoid burning. Add the remaining 2 tablespoons of margarine, apple, celery, and ground ginger. Sauté covered for 3-5 more minutes, continuing to stir at least once per minute. Stir in the vegetable stock and brown sugar.

In a cup or very small bowl, whisk the corn starch with the hot water until the corn starch is completely dissolved. Pour the corn starch mixture into the saucepan with the rest of the ingredients, and stir rapidly to incorporate and break up any clumps. Stir constantly while heating for another 2-3 minutes, or until the mixture is hot and has thickened slightly. Taste and add salt if necessary. Cover the sauce, and turn off the heat or reduce it to simmer/keep warm.

Bake or reheat your waffles (see note), and chop them into bite-size pieces.

Spoon waffle pieces onto serving plates, and spoon warm sauce onto each pile of waffle pieces just before serving.