Wash the peppers and dry them. Roast them using one of the following methods: grilling, broiling, or placing on stovetop burner until peppers are blackened all over.
Put them in a sealed bag or container and allow to steam for 15 minutes or until peels have loosened. Cut them in half, allowing hot condensation from inside to pour out. Then remove the seeds.
Remove the peels completely, then cut peppers into thin strips.
In a large pan over a medium flame, saute the garlic and leek in olive oil until softened. Add the chopped tomato pulp, and season to taste with salt and pepper. Let cook for five minutes. Then turn down the flame and add the peppers and cook everything for another fifteen minutes.
Meanwhile, cook the fettuccine to al dente in plenty of salted water, according to package directions. Add to the cooked sauce and serve immediately.