1. Cut the eggplant into quarters lengthwise, then dice into small pieces.
2. Finely slice the onion.
3. Pour olive oil and the vegetables into a pan, then sauté over low heat until they are colored, for a few minutes.
4. Reduce the heat, then add tomato paste, sage, and three tablespoons of water. Simmer covered for eight minutes.
5. In a pot, bring one liter of water to a boil. Add the pasta and cook according to the instructions on the package.
6. Drain the pasta, then mix it with the eggplant. Serve hot, with a sprinkle of grated pecorino cheese or a few drops of Tabasco sauce.