Add the raw cashews to a small bowl. Cover with water and allow the cashews to soak for about 6 to 8 hours (or up to overnight). Drain and rinse well.
Add the cashews and the broth to a blender. Process until completely smooth. Set aside.
For the pasta:
Bring a large pot of lightly salted water to a boil. Add the penne and cook until al dente, according to the package directions. Drain and set aside.
Meanwhile, add the olive oil to a large skillet set over medium heat. When hot, add in the onion and cook for about 5 minutes, until tender and starting to brown. Stir in the garlic and cook for 30 seconds, until fragrant. Stir in the tomato paste and cook for another 30 seconds.
Add the tomatoes (with their juices), the vodka, salt and red pepper flakes to the skillet. Let the mixture simmer, stirring occasionally, for 8 to 10 minutes, until reduced slightly and the alcohol smell has cooked off (reducing the heat as needed).
Turn off the heat and stir in the cashew cream. Add the drained pasta to the skillet and toss until combined. Taste and season with additional salt and red pepper flakes as needed.
Serve garnished with plenty of fresh basil or parsley.
Recipe time does not include time to let the cashews soak. Be sure to plan ahead.