In a high powered blender, add the cashews and water and blend until completely smooth. If there is any graininess to the cream, keep blending. This takes a couple of minutes.
Once the cream is smooth, add the tapioca starch and blend again for another 30 seconds. Set aside.
Heat the olive oil in a large skillet over medium heat. Add the shallot and garlic and cook until softened, stirring occasionally -- about 3 minutes.
Add tomato paste and cook, stirring occasionally, until paste is brick red and starts to caramelize -- about 5 minutes.
Add vodka and cook, stirring constantly, until liquid is mostly evaporated -- about 2 minutes.
Add cream and red pepper flakes and use a whisk to incorporate until well blended. Season with salt and pepper and remove from heat.
Meanwhile, cook the pasta in a large pot of boiling, salted water, stirring occasionally to prevent sticking, until pasta is al dente. Drain pasta, but reserve 1 cup of pasta cooking liquid.
Add pasta to the skillet with sauce along with vegan butter and 1 cup of pasta cooking liquid. Cook over medium-low heat, stirring constantly, until butter has melted, all of the cream is incorporated, and a thick, glossy sauce has formed -- about 2 minutes.
Season with salt and pepper and add 2 tbsp nutritional yeast (if using -- see recipe note #2).
Add 1/4 cup chopped fresh basil and toss to coat. Divide pasta among bowls and top with more basil.