1. Bring a large pot of salted water to a boil for the penne.
2. In a large saucepan, heat the 2 teaspoons oil with the garlic over low heat until the garlic begins to brown, about 3 minutes. Add the onion and 1/4 teaspoon salt, cover, and cook until the onion is softened, about 2 more minutes. Add the tomato, 1/2 teaspoon salt and the red pepper flakes. Bring to a simmer, reduce the heat and simmer very gently 10 minutes. Stir in the cream and evaporated milk and simmer 1 more minute.
3. Meanwhile, after the sauce has cooked 5 minutes, add the penne to the boiling water and cook until just shy of al dente, about 6 minutes. Drain, reserving about 1/2 cup pasta water. Add the drained penne to the saucepan and simmer until the penne is al dente, 1 to 2 minutes, adding a little of the pasta cooking water if the mixture is dry. Stir in 1/4 cup of the Parmesan, along with the basil and black pepper.
4. To serve, divide pasta among 4 serving bowls. Drizzle each serving with 1/2 teaspoon olive oil, and sprinkle with the remaining Parmesan.