Preheat the oven to 350°F. Spray a 9-inch deep pie plate or 9x13 casserole dish with nonstick spray.
Cook the spaghetti according to package directions. Drain well.
Toss the hot spaghetti with the beaten eggs, Parmesan cheese, and melted butter.
Press the spaghetti mixture into the prepared dish, creating a crust along the bottom and slightly up the sides.
In a large skillet, brown the ground beef and onion. Drain excess grease.
Stir in the garlic, pasta sauce, and Italian seasoning. Simmer the meatsauce for 5 minutes.
In a small bowl, combine the cottage cheese and cream cheese until smooth.
Spread the cheese mixture over the spaghetti crust.
Spoon the meat sauce evenly over the cheese layer.
Top with shredded Monterey Jack and Parmesan cheese.
Bake uncovered for 30–35 minutes, until hot and bubbly. Let stand for 10 minutes before slicing. Garnish with parsley if desired.
Notes
Store leftover Spaghetti Pie Casserole tightly covered in the refrigerator for up to 4 days. Individual portions reheat well in the microwave, making this a great option for easy lunches and quick dinners throughout the week.To freeze, allow the casserole to cool completely, then wrap the baking dish tightly with plastic wrap and aluminum foil or transfer portions to freezer-safe containers. Freeze for up to 3 months. Thaw overnight in the refrigerator before reheating.For best results, reheat larger portions in a 350°F oven for 20 to 25 minutes, or until heated through. Cover loosely with foil if the cheese begins to brown too quickly.