In a large skillet over medium heat, brown the ground beef until no longer pink; drain fat and stir in the marinara sauce.

In a medium mixing bowl, combine the softened cream cheese, cottage cheese, sour cream, Italian seasoning, garlic powder, and black pepper until well blended.

Grease the insert of a 6-quart slow cooker with non-stick cooking spray.

Spread one cup of the meat sauce at the bottom of the slow cooker.

Layer half of the cooked spaghetti noodles over the sauce.

Spread the entire cream cheese mixture evenly over the noodles.

Top with the remaining spaghetti noodles.

Pour the remaining meat sauce over the second layer of noodles.

Cover and cook on high for 2 to 3 hours or on low for 4 to 5 hours.

During the last 20 minutes of cooking, sprinkle the mozzarella and Parmesan cheese over the top and replace the lid until the cheese is melted and bubbly.