Place a large pot of salted water on to boil for the pasta. Place the cashews in a small bowl and add ½ cup hot tap water. Let nuts soak for at least 10 minutes. Rinse and dry the produce. Trim and discard the roots and any dark green leaves from the leek. Cut the leek in half lengthwise and then slice into half moons. Rinse sliced leeks well in a colander. Quarter the artichoke hearts.
Pat the leeks dry with a paper towel. Place a large nonstick skillet over medium-low heat with 2 tbsp olive oil. Add the leeks and cook, stirring occasionally, until soft (there should be only slight browning so reduce heat as necessary), about 8 to 10 minutes.
Halve the lemon. Add 1 tbsp lemon juice, the cashews and their soaking water, Dijon mustard, garlic, nutritional yeast, and a pinch of salt and pepper. Blend on high until smooth.
Add the Banza® cavatappi to the boiling water and stir. Reduce heat slightly and cook until al dente, about 6 to 8 minutes. Reserve ½ cup of the cooking water, then drain the pasta into a colander.
Set your oven to broil on low. Add the artichokes, cashew sauce, and reserved cooking water to the skillet with the leeks and bring to a simmer. Stir in the cooked cavatappi and season generously with salt and pepper.
Transfer artichoke cavatappi to a 8x8 baking dish and broil until the top layer is browned and crisp, about 2 to 4 minutes. In a medium bowl, combine the arugula, any remaining lemon juice, 1 tsp olive oil, and a pinch of salt and pepper. Toss lemon arugula to combine. Scoop baked artichoke cavatappi onto large plates and serve with lemon arugula.