Preheat oven to 350 degrees.
In a medium size pot, over medium to high heat, sauté onion in olive oil for 3-4 minutes. Add the thinly sliced potato, minced garlic, chopped carrots, garlic and onion powder, 1/2 teaspoon sea salt, and crushed red pepper. Sauté for 1 minute.
Add the soaked cashews and water. Let it simmer until the potato and carrots are cooked and soft.
Transfer to a blender and add nutritional yeast flakes, lemon juice, turmeric, margarine (optional), and salt to taste. Blend until smooth.
Cook macaroni according to the directions on the box, drain and mix with the cheese sauce.
Pour into a greased baking pan.
For the topping simply melt the margarine or oil and toss with the breadcrumbs. Sprinkle on the top of the mac and cheese.
Bake for 20 minutes in the oven. If you would like more of a golden color on top, broil for 2-3 minutes.
Cashews lose some of their distinctive taste and blend easily when soaked overnight. If per chance you did not remember to soak overnight, you can cook the cashews in a little bit of water for 15 minutes or so. This will have a similar effect. Be sure to drain the cashews before use.
This cheese sauce stores well in the fridge. It can be made ahead of time, and then heated and added to pasta right before serving.