Cook noodles according to the package directions. Drain, and then transfer to your serving dish.

Meanwhile, in a large pan, heat the butter or oil. Sauté the mushrooms over medium-high heat for two minutes. Add salt, pepper, and the garlic to the pan and sauté for one to two minutes. Add in the thyme and flour and stir until all the mushrooms are coated in the flour.

Pour in the water or vegetable broth, non-dairy milk, and Dijon mustard. Stir for another two minutes or more until the mixture comes up to a boil and thickens.

Remove from the stove and pour into drained noodles.  Mix thoroughly and season with salt and pepper to taste. Garnish with parsley and scallions.