Carve tomatoes crosswise, pour boiling water over them and peel off the skin. Cut the tomatoes into quarters and remove the seeds. Halve pepperoni lengthwise, remove seeds and ribs. Cut fennel into quarters and remove the stalk.
Cut the fennel into fine strips. Pluck the basil leaves. Press garlic through a garlic press. Put the pasta in plenty of boiling salted water and cook for 12-14 minutes until al dente. Sauté the fennel in hot olive oil.
Add the tomatoes, pepperoni and garlic and sauté. Stir in balsamic vinegar and season to taste with salt and pepper. Drain the pasta. Arrange noodles and sauce garnished with basil on 4 plates.