For the gravy, place a high-sided sauté pan or Dutch oven over medium-high heat and add enough olive oil to coat the bottom. Once hot, add all of the ground meat and cook until brown, about 10 minutes, breaking it up with the back of a spoon as it cooks. Add the garlic, season with salt and pepper, and continue to cook a few more minutes. Add the crushed tomatoes, tomato purée, basil leaves, sugar to taste and the butter. Bring up to a bubble and simmer for 30-45 minutes, stirring occasionally.
Once you have the gravy cooking, prepare the lasagna noodles: Place a large pot of water over high heat and bring to a boil. Add some salt and the lasagna noodles, and cook according to package directions, stirring frequently to prevent sticking. Drain and run under cold water until completely cool. Reserve noodles.