• Preheat oven to 350° Fahrenheit. Position oven racks so that baking dish sits in center of oven during baking.

For the Spaghetti

• Fill large pot with 16 cups water. Place pot on stovetop over medium-high heat and bring water to rolling boil. Once water begins to boil, add 1 tablespoon sea salt and stir to incorporate.
• Bring salted water to rolling boil. Once boiling, add 1 pound dry spaghetti. Cook spaghetti according to package instructions, reducing cook time on packaging by 1 minute.
• When spaghetti is al dente, remove 2 to 4 tablespoons water from pot if desired and set aside. Pour pasta and remaining water into colander.
• Drain pasta well, then transfer pasta to baking dish and spread pasta out into one even layer. Set baking dish aside.

For the Meat Sauce

• Place large skillet on stovetop over medium heat. Add 1 pound lean ground meat of choice, 1 cup diced yellow onion, and 2 teaspoons minced garlic to skillet. Cook, stirring and breaking up ground meat as needed, until meat is no longer pink.
• Once meat is cooked, add 1 24-ounce jar tomato pasta sauce to skillet and stir to incorporate.
• Reduce heat to low and simmer, stirring occasionally, until sauce has thickened, approximately 3 to 5 minutes. If desired, stir in small amounts of reserved pasta water to thicken sauce more. Continue stirring sauce occasionally while preparing alfredo sauce.

For the Homemade Alfredo Sauce

• Place second large skillet on stovetop over low heat. Add 8 tablespoons unsalted butter and 2 cups heavy cream to skillet. Gently stir constantly until butter has melted.
• Once butter has melted, add ½ teaspoon freshly cracked black pepper, 1 teaspoon salt, and 1 teaspoon garlic powder. Continue stirring to incorporate seasonings.
• Remove skillet from heat and let mixture cool slightly, then add 2 cups grated parmesan cheese. Stir gently until parmesan is incorporated and beginning to melt, then return skillet to low heat. Continue stirring until parmesan is completely melted and sauce has thickened, approximately 2 to 3 minutes.

For the Spaghetti Alfredo

• Pour alfredo sauce into baking dish with spaghetti. Stir or toss noodles in sauce until completely covered, then spread spaghetti and sauce into even layer, covering bottom of baking dish completely.
• Top spaghetti layer with prepared meat sauce, spreading sauce evenly across top of spaghetti and covering pasta completely.
• Sprinkle 2 cups shredded mozzarella evenly across top of meat sauce layer, covering sauce completely.
• Place baking dish in preheated oven. Bake spaghetti alfredo 20 minutes or until mozzarella is melted and bubbly.
• Once mozzarella is ready, carefully remove baking dish from oven and set aside. Let dish rest 3 to 5 minutes, then divide into preferred portions and serve warm with desired sides.