In a large pot of salted boiling water, cook the fettuccine according to package directions until al dente. Drain and set aside, reserving a cup of the pasta water.
In a large skillet over medium heat, add olive oil. Once hot, add the ground beef, breaking it apart with a spoon. Cook until browned, about 5-7 minutes.
Add the diced onion and minced garlic to the skillet with the beef. Sauté for another 3-4 minutes until the onion is translucent.
Reduce the heat to low and stir in the heavy cream, cream cheese, shredded cheddar, and Parmesan cheese. Continue stirring until melted and smooth. Add Italian seasoning, salt, and pepper to taste.
Add the cooked fettuccine to the skillet with the sauce. Stir until the pasta is fully coated. If the sauce is too thick, gradually add reserved pasta water until you reach your desired consistency.
Gently fold in the cherry tomatoes, diced cucumber, and chopped green onions. Let it heat through for another minute.
Once everything is combined and warmed, remove from heat. Serve hot, garnished with fresh parsley on top.
Notes
Serve in deep bowls with extra cheese and parsley on top. Add a lime wedge for a fresh touch.