This may need more perfecting but it was easy, and cheese-eating housemate liked it. I based this on Happy Herbivore's recipe from her recent cookbook, but I substituted soy yogurt for yellow miso (because I don't have it and it's high in sodium) and I used different amounts of things.
Cook up some macaroni (I started with 2/3 cup dry for 2 small servings). I used corn macaroni. About halfway through, I threw in some peas because housemate and I love peas and macaroni and cheese.
While doing that, make some sauce (the measurements aren't exact yet)
2 Tbsp nutritional yeast
1/2 cup non-dairy milk (I used almond milk)
2 Tbsp soy yogurt
1/2 tsp onion powder
1/2 tsp garlic powder
1/4 tsp paprika
1/4 tsp turmeric
2 tsp cornstarch (optional, I didn't have any but it might be a good idea)
Whisk it all together, heat up a bit on the stove.
Drain the water from the macaroni and peas, add the sauce, stir, serve. This makes two fairly small servings. If you want more than a side dish, double the recipe.