Step 1

Bring a large pot of salted water to boil for the pasta. Cook according to package directions. If using broccoli, stir it into the pot when just 2 to 3 more minutes remain. Drain, and transfer the contents to a large serving bowl.

Step 2

Meanwhile, in a medium-to-large saucepan, warm the oil over medium heat. Add the onion and a pinch of salt and cook, stirring often, until the onion is tender and turning translucent, about 5 minutes.

Step 3

Add the grated potato, garlic, garlic powder, onion powder, mustard powder, salt and red pepper flakes. Stir to combine, and cook, stirring constantly, for about 1 minute to enhance their flavors.

Step 4

Add the cashews and water, and stir to combine. Let the mixture come to a simmer. Continue simmering, stirring frequently and reducing heat as necessary to avoid a rapid boil, until the potatoes are completely tender and cooked through, about 5 to 8 minutes.

Step 5

Carefully pour the mixture into a blender. Add the nutritional yeast and 2 teaspoons vinegar. Blend until the mixture is completely smooth, about 2 minutes, stopping to scrape down the sides if necessary. If the mixture won’t blend easily or if you would prefer a thinner consistency, add water in ¼ cup increments, blending after each one.

Step 6

Taste, and blend in additional salt until the sauce is utterly irresistible (I typically add at least another ½ teaspoon). If it needs a little more zip, add the remaining teaspoon of vinegar. Blend again.

Step 7

Pour the sauce into the bowl of pasta. Stir until well combined, and serve immediately. Leftovers keep well, chilled and covered, for 3 to 4 days. Gentle reheat, adding a tiny splash of water if necessary to loosen up the sauce.