Preheat your oven to 350°F (175°C).

In a large skillet, brown the ground beef and Italian sausage over medium heat, breaking it up as it cooks. Season generously with salt and pepper. Once browned, drain most of the fat, leaving just a bit for flavor. Add the chopped onion and minced garlic to the skillet, cooking until the onion becomes translucent and fragrant. Pour in the marinara sauce, reserving ½ cup for later, and stir to combine. Set this aside.

Boil the spaghetti according to package directions, aiming for an al dente texture. Drain the pasta, then transfer it to a large mixing bowl. Toss the hot spaghetti with the butter and the reserved ½ cup of marinara sauce until the noodles are evenly coated.

In a separate bowl, thoroughly mix together the softened cream cheese, sour cream, and cottage cheese until smooth and creamy.

Take half of the buttered spaghetti and spread it in the bottom of a 9×13-inch baking dish. Smooth the cheese mixture evenly over the noodles. Add the remaining spaghetti on top of the cheese layer. Finally, spread the meat sauce over the top, ensuring an even layer. Sprinkle the shredded mozzarella and grated parmesan over the entire dish.

Place the dish in the oven and bake for 30 to 40 minutes, or until the cheese is melted, golden, and bubbly. Around the 20-minute mark, check if the cheese is browning too quickly; if so, loosely cover the dish with foil. Once baked, let the dish sit for at least 15 minutes before slicing, allowing it to set. Serve and enjoy!