Bring a large pot of well-salted water to a boil. Cook the gluten-free fettuccine according to package directions until al dente. Before draining, scoop out and reserve 1/2 cup pasta water. Drain the pasta and set aside.

Heat a large skillet over medium. Add a tablespoon of neutral oil or a splash of water/broth. Add minced garlic and chopped sun-dried tomatoes. Sauté for 1–2 minutes, stirring, until the garlic softens but doesn’t brown. Add a tablespoon of water if the pan looks dry.

Stir in Italian seasoning, balsamic vinegar, and tomato paste. Cook for 2–3 minutes, scraping the pan so the tomato paste darkens slightly; this concentrates flavor.

Add the cherry tomatoes and 1/2 cup water or vegetable broth. Cover and cook for 3–4 minutes until the tomatoes begin to collapse. Uncover and gently smash a few tomatoes with the back of a spoon to release their juices.

Pour in the coconut milk and stir in nutritional yeast. Season with salt and pepper. Reduce heat and simmer for 5–10 minutes until the sauce thickens. If the sauce becomes too thick, add reserved pasta water a tablespoon at a time to loosen it.

Add the drained pasta directly to the skillet. Toss with the arugula until it wilts and everything is well coated. Taste and adjust seasoning with salt, pepper, or a splash more balsamic for brightness.

Scatter chopped parsley and a sprinkle of vegan parmesan if using. Serve immediately while warm.