Cook the pasta in boiling salted water for about 5 minutes. Clean, wash and drain the leek and cut into rings. Wash tomatoes, dab dry and cut in half. Drain noodles, rinse with cold water and drain well.
Dab meat dry and cut into thin strips. Heat oil in a wok. Stir-fry the meat for about 5 minutes. Season with salt and pepper. Remove from the wok. Fry the leek in the cooking fat for 3-5 minutes.
Add tomatoes, pasta and meat. Mix soy sauce and sherry, pour on and heat together while stirring. Season if necessary.