Preheat the oven to 375 degrees F.: When the oven reaches 375 degrees F you will have the proper environment for even baking, allowing the filling to heat through while the top browns. You should feel warm air when you open the door and hear a low hum as the elements cycle. If the oven is not fully preheated before you put the lasagna in, the layers can take longer to set and may become overbrowned before the center is hot. A common mistake is assuming the oven is ready the moment the dial clicks, so use an oven thermometer if you want exactness.
Bring a large pot of water to a boil and generously season with kosher salt. Cook the lasagna noodles until al dente, according to package instructions. Drain and rinse with cold water. Separate any noodles that are stuck together. Drizzle the noodles with a little olive oil.: After the water is roaring, the salt should give the boiling water a faint minerally scent, which seasons the lasagna noodles as they hydrate. The noodles should have a slight bite when you test them, not mushy. Rinsing with cold water removes surface starch and halts cooking, which also keeps them from fusing. Drizzling a bit of olive oil and separating any sticking pieces ensures smooth layering. One oversight is overcooking the noodles; they will finish in the oven, so aim for al dente to maintain texture.
In a large pot, heat the olive oil over medium-high heat. Add the sausage and ground beef, season with salt and pepper. Cook, stirring occasionally, until browned, about 8 minutes. Drain excess grease.: As the olive oil warms you will smell the oil shimmer, then when the meats hit the pan they will sizzle and begin to brown, releasing savory aromas. Browning generates complex Maillard flavors that make the sauce deep and meaty. Stir occasionally to ensure even browning and to break meats into small pieces. If you leave grease in the pan the lasagna can become greasy, so drain well. A typical error is crowding the pan, which steams the meat instead of browning it, so use a wide pot.
Add the marinara sauce to the cooked sausage and meat and stir to combine.: When the Easy Marinara Sauce hits the hot meat you will hear a brief hiss and see the sauce loosen, coating the browned bits and lifting those concentrated flavors. This melding creates a unified sauce that clings to the noodles. Stir thoroughly so no dry pockets remain. If the sauce seems too thick, a splash of reserved pasta water or a little broth can thin it, but avoid watering it down excessively. A common slip is under seasoning after adding sauce, so taste and adjust salt and black pepper if needed.
In a large bowl, combine the ricotta cheese and eggs. Add the heavy cream and lemon juice and stir until smooth. Stir in 1 cup shredded mozzarella cheese and 3/4 cup Parmesan cheese. Season with salt and pepper.: The texture should become silky and slightly glossy as the ricotta cheese and eggs emulsify with the heavy cream . The lemon juice brightens the dairy, preventing flabbiness and adding clarity to the filling. Fold in the mozzarella and Parmesan cheese so pockets of cheese will melt beautifully in the bake. Be cautious not to overbeat the mixture, which can make it too loose. If the ricotta is watery, drain briefly to concentrate the texture.
Spread 1 1/2 cups of sauce on the bottom of a 9×13 baking dish that is at least 2 1/2 inches deep. Top with a layer of noodles, try not to overlap them.: A thin bed of sauce at the bottom prevents sticking and starts every slice with a moist foundation. Arrange the lasagna noodles so they cover the sauce evenly, leaving small gaps for the sauce to flow. The visual cue is a smooth, even surface before adding more fillings. Overlapping too much can make thick, uneven bites, so place them edge to edge for consistent structure.
Top with 2 cups of sauce and 1/2 cup shredded mozzarella cheese. Top with another layer of noodles and spread ricotta cheese mixture evenly over the noodles.: The sauce should look glossy and simmered, coating the noodles. Sprinkling mozzarella adds early melt pockets, and the ricotta layer provides a creamy counterpoint. Use a spatula to spread the ricotta in an even sheet so each slice has balanced creaminess. Avoid plopping large dollops that will create voids; smooth distribution gives a uniform mouthfeel.
Add another layer of noodles, 2 cups of sauce, and 1/2 cup of shredded mozzarella cheese.: Repeat the visual rhythm so the lasagna builds height and balanced flavor. At this point you should notice alternating bands of bright red sauce and pale cheese, which promise contrasted bites. Press lightly to compact layers for stability. If the pan is overfilled, the lasagna may bubble over when baking, so maintain even layers and leave a small gap under the rim.
Top with another layer of noodles and finish with remaining sauce, mozzarella cheese, and Parmesan cheese. The pan will be very full.: The final top should be a generous coat of sauce and an even sprinkle of mozzarella and Parmesan cheese . The cheeses will brown and bubble, forming a golden, fragrant crust. If you want more crust, uncover toward the end of baking. Watch for excessive browning, which can happen quickly, and tent with foil if needed.
Tent the lasagna with foil and secure tightly all around the edges. Place lasagna pan on a baking sheet and bake for 40 minutes. Carefully remove foil and bake an additional 15 to 20 minutes or until hot and bubbly.: Tenting with foil traps steam so the interior heats evenly without overbrowning the top. The baking sheet catches any spills and makes the pan easier to move, while the oven will fill with a heady scent of simmered sauce and melted cheese. When you remove the foil the top should start to blister and brown, and you will hear a lively bubble. A misstep is opening the oven door too often, which drops heat and lengthens bake time.
Remove from oven and let the lasagna sit for 15 minutes before serving. Garnish with fresh basil or parsley, if desired. Serve warm.: Resting lets the layers set and firm so slices hold their shape, and the steam that settles carries the aromas of basil or Italian parsley . The surface will calm into a cohesive cake like structure ready to plate. Cutting too soon causes a sloppy presentation, so be patient for a neat, satisfying slice.
