Wash the chicken fillets and pat them dry. Season with salt and pepper. Heat the oil in a pan and fry the chicken fillets for about 6 minutes while turning. Meanwhile cook the noodles in boiling salted water for about 8 minutes.
Wash, clean and halve the tomatoes. Peel onion and cut into fine slices. Wash the basil, dab dry and pluck. Add the tomatoes and onion to the chicken fillets about 1 minute before the end of the cooking time and braise.
Remove the chicken fillets, tomatoes and onions and keep warm. Add stock and lemon juice. Stir in mascarpone and lemon peel and simmer for about 1 minute. Season with salt and cayenne pepper.
Drain the pasta and retain some cooking stock. Mix the noodles with the lemon-mascarpone sauce and arrange on a plate. Cut the chicken fillets into slices about 2 cm thick and arrange on the noodles with the tomatoes.
Cut basil into rough strips and sprinkle on the chicken fillets.