Instructions:
Preheat the Oven:
Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius).
Cook the Spaghetti:
In a large pot, bring water to a boil and add a teaspoon of salt.
Add the spaghetti noodles and cook according to the package instructions until al dente.
Drain the noodles and set aside.
Prepare the Ground Beef:
In a large skillet, heat the olive oil over medium heat.
Add the ground beef and cook until browned, breaking it up with a spoon as it cooks.
Season with salt, pepper, and Italian seasoning.
Once the beef is cooked, drain any excess fat and add half of the marinara sauce to the skillet. Stir to combine and set aside.
Make the Cheese Mixture:
In a medium bowl, combine the ricotta cheese, sour cream, shredded mozzarella cheese, grated Parmesan cheese, and the egg. Mix until well combined.
Add a pinch of salt and pepper to taste.
Assemble the Casserole:
In a greased 9×13 inch baking dish, layer half of the cooked spaghetti noodles.
Spread half of the cheese mixture evenly over the noodles.
Add the remaining noodles on top of the cheese mixture.
Spread the remaining cheese mixture over the top.
Pour the remaining marinara sauce over the top, ensuring it covers the entire casserole.
Add the cooked ground beef mixture on top, spreading it evenly.
Sprinkle additional shredded mozzarella and Parmesan cheese on top if desired.
Bake the Casserole:
Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes.
After 30 minutes, remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly.
Serve and Enjoy:
Remove the casserole from the oven and let it sit for a few minutes before serving.
Garnish with fresh basil or parsley if desired.
Cut into squares and serve warm.