Rinse the tomatoes, cut them in half and set aside. For refinement, you can also skin the tomatoes before cutting them in half.
Rinse the tarragon, shake dry, and pluck the leaves from the stems. Peel the garlic. Whisk the Parmesan in small pieces together with the remaining ingredients (except tomatoes) in a food processor to a pesto. While whisking, slowly add the oil.
Serve the spaghettini cooked al dente with the pesto and the tomatoes.
Our tip: As an alternative to fresh herbs, you can also use frozen ones – these are also characterized by a fresh taste!