Soak the cashews: If using cashews, cover them with hot water and soak for 20–30 minutes, then drain. For a make-ahead option, soak overnight in cool water. If using cauliflower, steam until very soft.

Boil the pasta: Bring a large pot of salted water to a boil. Cook pasta until just al dente. Reserve 1 cup of pasta water, then drain.

Sauté the garlic: In a large skillet over medium heat, warm the olive oil. Add the garlic and cook 1–2 minutes until fragrant and slightly golden. Do not brown it or it will taste bitter. Remove from heat and set aside.

Blend the sauce: In a high-speed blender, combine soaked cashews (or cauliflower), plant milk, vegetable broth, nutritional yeast, miso, lemon juice, onion powder, salt, pepper, and the sautéed garlic with its oil. Blend until completely smooth and creamy. If it’s too thick to blend, add a splash more broth.

Warm and season: Pour the sauce back into the skillet over low heat. Stir in vegan butter if using. Taste and adjust seasoning: add more salt, pepper, lemon, or nutritional yeast to balance richness and brightness.

Toss with pasta: Add the cooked pasta to the skillet and toss until evenly coated. Use reserved pasta water, a few tablespoons at a time, to loosen the sauce and help it cling. You’re aiming for glossy and silky, not heavy or gloopy.

Finish and serve: Sprinkle with chopped parsley, a pinch of red pepper flakes if you like heat, and vegan parmesan or extra nutritional yeast. Serve hot.