Cook the pasta according to the package instructions. Drain and set aside.
In a high-powered blender, combine the soaked cashews, water, nutritional yeast, lemon juice, Dijon mustard, garlic powder, onion powder, and turmeric. Blend until smooth and creamy. Set aside.
In a large saucepan, melt the coconut oil or vegan margarine over medium heat. Add the flour and whisk constantly for about 2-3 minutes to create a roux.
Gradually pour the cashew mixture into the saucepan, whisking continuously to avoid lumps. Continue to whisk until the sauce thickens, about 5-7 minutes.
Once the sauce has thickened, season with salt and pepper to taste. Adjust the consistency by adding more water if needed.
Combine the cooked pasta with the cheese sauce, stirring until the pasta is well coated.
If desired, transfer the mac and cheese to a baking dish, sprinkle with bread crumbs, and broil for a few minutes until the top is golden brown and crispy.
Serve the vegan Old Fashioned Mac and Cheese hot and enjoy!