Prep the Pasta:
Bring a large pot of water to a boil, add 1/2 teaspoon of salt, and cook the rotini according to package instructions. Drain and set aside.
Sauté the Vegetables:
In a large skillet, heat the olive oil and butter over medium heat.
Add the minced garlic, diced green bell pepper, diced onion, and sliced mushrooms. Sauté for 3-4 minutes until the vegetables are tender.
Cook the Beef:
Add crumbled sirloin (or ground beef) to the skillet. Season with 1/2 teaspoon of salt and 1/2 teaspoon of black pepper. Cook until the beef is no longer pink, then drain off excess fat.
Combine with Sauce:
Stir in the jar of red pasta sauce and heat through.
Prepare the Cheese Mixture:
In a medium mixing bowl, combine the softened cream cheese, sour cream, and cottage cheese (if using). Blend using a hand mixer until smooth and well mixed.
Layer the Dish:
In a greased 9 x 12 inch baking dish, layer half of the cooked pasta. Spread the cheese mixture evenly over the pasta, then add the remaining pasta. Top with the meat sauce.
Bake:
Cover the dish with foil (spray the foil with oil to prevent sticking) and bake in a preheated oven at 350°F (175°C) for 20 minutes.
Add Cheese and Finish Baking:
Remove the foil and sprinkle grated cheese on top. Return to the oven for an additional 10-15 minutes, or until the cheese is melted and bubbly.
Rest and Serve:
Let the dish rest for 5 minutes before serving.
Enjoy your delicious spaghetti with meat sauce!
