Cook the Bacon : In a skillet, cook the bacon until crispy. Drain on paper towels, crumble, and set aside.

Prepare the Pasta : Bring a large pot of salted water to a boil. Cook the spaghetti according to package instructions until al dente. Drain and set aside.

Make the Sauce : In a large skillet or pot, heat the olive oil over medium heat. Add the chopped onion and sauté for 3–4 minutes until translucent. Add the minced garlic and cook for another 1 minute. Pour in the milk, cream of chicken soup, and softened cream cheese. Stir until the cream cheese is fully melted and the mixture is smooth.

Season the Sauce : Add the salt, black pepper, and crumbled bacon (reserve some for garnish). Stir well.

Combine the Pasta : Add the cooked spaghetti to the skillet and toss to coat evenly with the sauce. Mix in the mozzarella and cheddar cheeses until melted and creamy.

Garnish and Serve : Transfer the pasta to a serving dish. Garnish with fresh parsley and the reserved crumbled bacon. Serve hot with a side of garlic bread or salad.