Mix flour, yeast, margarine, and enough soy milk to mix and make pasty in a saucepan. Heat over medium till slightly bubbly. Add garlic powder. Slowly add in remaining soy milk, beating with a whisk. Add salt and cook till thickens to a desired consistency, adding water if needed.
I usually make this thick, and it cools into more of a spread-like sauce which can be spread on bread. It's really good on baking powder biscuits right out of the oven.
I also add about 2 tablespoons water per 3 tablespoons sauce when pouring it over pasta.
This is really good mixed with broccoli in the sauce for a kind of broccoli-cheese like sauce.