Prep your vegan heavy cream by pouring boiling water over cashews in a small bowl. Set aside and let sit until cashews become soft.
Meanwhile, boil water for pasta. While waiting for the water to boil, chop onion and garlic and place into a separate sauce pan with olive oil. Cook until onions are soft and translucent.
Water should be boiling by this point, so add pasta and cook until al dente. Meanwhile, add tomato paste to pan with onions and garlic and sauté until caramelized.
While pasta is boiling and sauce is caramelizing, prepare your vegan heavy cream by adding cashews (rinsed and drained) to a blender with oat milk and coconut cream and blend until smooth.
Once pasta is ready, reserve 1/4 cup of pasta water and set aside before draining and rinsing pasta with cold water. Set aside.
Add 1/2 cup of vegan heavy cream to sauce pan with vodka and chili flakes. Season with salt and pepper and stir until smooth.
Add pasta, pasta water, and vegan butter to sauce pan and stir gently to combine.
Add dried basil, fresh spinach, and Parmesan shreds and fold to combine before serving.