Cook the macaroni according to package directions. If using broccoli, add it to the pot of boiling water in the last 2-3 minutes. Drain and set aside.
Meanwhile, add a few tablespoons of olive oil to a large pot over medium heat. Add the onion and cook, stirring often, until the onion is tender, about 5 minutes.
Add the garlic, grated potato, pimento, and seasonings. Stir to combine.
Add the cashews and non-dairy milk and stir to combine. Let the mixture come to a simmer and cook until the potatoes are completely soft, about 10 minutes. Add more milk if needed.
Carefully transfer the mixture into a blender or food processor. Add the nutritional yeast and rice wine vinegar. Blend until the mixture is completely smooth. Add a bit more non-dairy milk if it’s too thick.
Taste the sauce, and blend in more seasonings as needed. It may need more salt, vinegar, or nutritional yeast.
Pour the sauce back into the large pot (heat turned off). Add in the cooked macaroni and broccoli, and stir until combined.
Adapted From: Cookie and Kate