Heat 1 tablespoon of the olive oil in a saucepan on medium heat. Brown ground lamb in saucepan over medium-high heat until cooked through and no longer pink in the middle, about 8 minutes. Drain excess fat. Remove from pan and set aside.
Heat remaining olive oil in same saucepan.
When the oil is hot, add the onions and garlic. Cook until the onions start to get soft (but before they get brown), about 5 minutes.
Add the tomatoes, tomato paste, salt, pepper, and Italian seasoning. Mash up the whole tomatoes into smaller chunks.
Keep heating sauce until it starts to bubble (a.k.a. simmer), then turn the heat to low, and simmer uncovered for 25 minutes, adding cooked lamb when there's 5 minutes left to go.
For the fettuccine, a good time to start boiling the water is just before you add the tomatoes to the sauce. Fill a large pot with water. Bring to a boil, and cook for the time directed on the pasta box.
When the fettuccine is cooked, drain it and put it in a large bowl. Add the sauce. Serve!