1/4 cup nutritional yeast
1/4 cup all-purpose flour
1or 2 teaspoon arrowroot powder
1 teaspoon or so salt
1/2 teaspoon mustard powder
1/2 teaspoon paprika
1/2 teaspoon madras curry powder
1/4 teaspoon garlic powder
1/4 teaspoon onion powder
1/2 to 3/4 cup soy milk
2 or 3 tablespoon margarine
2 tablespoon vegan cream cheese spread (Tofutti's Better than Cream Cheese is great)
A few teaspoons malt vinegar (or other table vinegar)
In a small saucepan (but not too small), dump the yeast, flour, arrowroot powder and spices (save the salt for later) and whisk it all up until you can't tell which is which. Now, crank the heat up to medium-high and begin pouring in the soymilk, whisking all the time. Keep pouring until the mess in the pan seems too milky to be a good spread (it should be like a thin cream sauce), and keep on whisking until the stuff begins to rapidly thicken (don't be scared--if it seizes up and starts to look like the blob you're doing it right). Don't worry if it looks really gross and lumpy at this point, that's what tinkering is for. Whisk for thirty seconds or so more and then turn off the heat. Add the margarine and whisk it all up until there are no more large lumps and the margarine is fully incorporated. Taste it a bit (a chef who doesn't taste is like a blind racecar driver), and adjust the seasonings to your liking (this would be a good time to add that salt).
Once it seems that the spread is all finished, add the cream cheese and mix it thoroughly. Finally, stir in a couple of teaspoons of malt vinegar to round out the flavor, and you're done!
Spread it on bread and toast it for a great grilled cheese (I'm eating one right now, in fact). Dump it on macaroni (fun shapes, preferably) for a rocking macaroni and cheese. Heck, use it any place you'd use (heavily processed) cheese.
And feel free to tinker with the recipe. Make it your own. Add some different seasonings: marjoram and a little chili powder goes great on macaroni, or try some vegan Worcestershire sauce for something very akin to cheez whiz (not that that's necessarily a plus). But, as always, enjoy.