Cook the pasta as instructed on the package. Drain and set aside.

Pour the olive oil into a pan, melt the butter, and then stir-fry the onion, garlic, and tomatoes. Cook until slightly browned.

Shred the sardines, add them to the pan, and cook for another minute while stirring.

Add the tomato paste, season with salt, pepper, and basil, and cook for 3 more minutes.

Mix the pasta, sardine sauce, scallions, and parmesan.