Cook the pasta. Bring a large pot of generously salted water to a boil. Cook the penne according to package instructions until just al dente — usually 1–2 minutes less than the package says. Before draining, scoop out about 1 cup of pasta water and set it aside. Drain the pasta and set aside.
Sauté the aromatics. In a large pan over medium heat, melt the butter. Add the shallot and cook for 2–3 minutes until softened and translucent. Add the garlic and red pepper flakes and cook for another minute, stirring constantly so nothing burns.
Caramelize the tomato paste. Stir in the tomato paste and cook for 2–3 minutes, stirring constantly. You're looking for it to deepen in color slightly and smell slightly caramelized. This is the most important step — it's where the sauce gets all of its depth and richness. Do not rush it.
Add the vodka. Pour in the vodka and stir to combine. Let it cook for 2–3 minutes, allowing the alcohol to evaporate. You'll notice the sauce thickens slightly and the sharp alcohol smell fades. This is what you want.
Add the cream. Reduce the heat to low and pour in the heavy cream. Let the sauce simmer gently for about 5 minutes, stirring occasionally, until it thickens and turns a beautiful orange-pink color. Never let it boil aggressively — the cream can split if it gets too hot.
Combine pasta and sauce. Add the drained penne directly into the sauce. Toss everything together well, adding reserved pasta water a small splash at a time until the sauce is glossy and coats every piece of pasta perfectly. Stir in the freshly grated Parmesan.
Season and serve. Taste and adjust salt and black pepper as needed. Plate immediately, topped with extra Parmesan, a drizzle of olive oil, and fresh basil or parsley. This pasta is best served hot and fresh — enjoy!