Saute onion and garlic in a tablespoon of olive oil until tender and translucent. In large saucepan, add the onions garlic, and Ragu sauce and stir over low heat. Add in parsley, and other seasoning. Bring to a boil over high heat, and then reduce the heat and let simmer, covered, for 30 minutes.
Crumble the ground beef in a large skillet. Cook over medium-high heat until fully cooked, with no pink color remaining. Drain the fat from the meat, and then add the ground beef to the stockpot. Simmer for 20 more minutes.
Cook the pasta according to the package directions. Cover the bottom of a 13 by 9 by 2-inch pan with sauce. Add a layer of pasta and then a little less than 1/2 of each cheese; repeat the layers, ending with the sauce. Bake in the oven for 30 minutes. Top the casserole with the remaining cheese, return it to the oven, and continue to cook until the cheese is melted and bubbly, about 5 more minutes. Cut into squares before serving.
The Ground Beef Foundation
Ground beef anchors this dish, providing both protein mass and rendering fat that carries aromatics. Crumbling the meat finely ensures an even distribution throughout the sauce rather than heavy clumps. Drain excess rendered fat after browning over medium-high heat so the final sauce remains glossy rather than greasy. Simmering the beef directly in the tomato base for 20 minutes allows the muscle fibers to relax and absorb the herbal seasonings.
Pasta and Cheese Architecture
Spaghetti acts as the structural matrix, requiring strict adherence to package directions to prevent mushy starches. Undercooking the pasta by one minute prevents structural collapse during the 35 minutes of total oven exposure at 350 degrees. Cheddar and Monterey Jack cheeses behave differently under heat. Cheddar contributes sharp flavor compounds and low moisture, while Monterey Jack melts smoothly due to high fat-to-protein ratios. Layering these cheeses internally creates pockets of bind, while reserving the final handful for the last five minutes prevents burnt milk solids.
Storage and Make-Ahead Dynamics
Casseroles assembled ahead of time require extended baking windows. Cover chilled pans tightly with foil for the first 35 minutes to steam the interior before browning the top cheese layer uncovered. Freezing unbaked pans alters starch hydration; thaw completely in a refrigerator for 24 hours before applying heat to guarantee uniform internal temperature rise.