Preheat your oven to 375°F (190°C). Turn on your convection fan if you have one. Lightly oil a 9 x 13 inch baking pan.
Splash some olive oil into a large saucepan over medium-high heat. Add the onions and garlic, sautéing until they heat through and lightly colour. Add the tomatoes, oregano, bay leaves, ground beef, sausage meat, salt, lentils, and water. Stir vigorously with a wooden spoon, breaking the meat up into small pieces. By not browning the meat you also avoid toughening it and the long simmering time that would then be necessary to tenderize it. Continue stirring and cooking until the entire mixture is simmering and ready for lasagna assembly, about 20 minutes in total.
To make the cheese sauce, simply whisk together the eggs, the heavy cream, and the four cups of mozzarella, ricotta and parmesan cheeses.
To assemble the lasagna, layer the ingredients in the pan in this order: Two cups (500 mL) or so of the meat sauce, a layer of noodles, half of the cheese sauce, another noodle layer, another meat sauce layer, another noodle layer, the remaining cheese sauce, another noodle layer, the remaining meat sauce and last but not least, a thick layer of mozzarella with the last cup.