Preheat oven to 400°
In a large pot, combine the milk, sourp, and cream cheese. Simmer over medium heat, stirring regularly
Once the cream cheese is fully melted, stir in 2 cups of shredded cheese, garlic powder, onion powder, salt, and pepper
Break spaghetti in half and add it to the bubbling hot cream cheese pasta sauce
Cook the noodles in the sauce until al dente (about 8-10 minutes)
Transfer the noodles and sauce to the baking dish prepared with non-stick spray
Bake for 15 minutes and serve!