1. Blend avocado, egg yolk, garlic, and lemon juice in a powerful blender or food processor. Pulse to blend and add heavy cream gradually. Blend the sauce until smooth and set aside.
2. Cut up strips of bacon and cook in a large pan. Set aside.
3. In a large pot, bring water to a boil and cook the spaghetti according to the package instructions. Drain and coat with olive oil. Add sauce, bacon, parmesan, and salt and pepper, stirring until well-combined. Enjoy!