1. Preheat oven to 350 degrees F and lightly spray baking dish, if baking. Cook pasta according to package directions. In the last 4-5 minutes of the pasta cooking, start making the sauce. Combine all dry ingredients (flour, nutritional yeast, salt and spices) in a medium pot. Do not turn on heat yet.
2. Add the milk and veggie broth. Whisk to incorporate all ingredients and get all the lumps out. Now turn on the heat to medium high. Keep whisking/stirring as the sauce heats because it will start to get thick pretty fast. Once it gets nice and thick. turn off the heat and add the umeboshi vinegar, mustard, soy sauce and vegan margarine.
3. Mix well. If you didn't use the umeboshi vinegar, you can add more soy sauce if you think it needs it. If your sauce ends up too thick to your liking, just add a little more milk or veggie broth to thin it out. When pasta is finished cooking, drain it and put it back in the pot that it was cooked in.
4. You have 2 options to serve this. You may go ahead and pour all of the cheese sauce on the pasta (there will be a lot!) and stir until everything is combined. Serve the cheesy goodness as is.
5. Or, you can mix about 3/4 of the sauce with the pasta, put it in prepared dish, and then pour the remaining cheese sauce on top. Sprinkle breadcrumbs on top and bake for 15 minutes, until browned.
Hope you like it! I love it so much that I crave it almost once a week!