Begin with fresh asparagus spears — trim off the woody ends and cut the asparagus into pieces of about 1 cm each (about 1/2 inch). If you’re using pre-cleaned frozen asparagus, you can skip this step.
Heat a non-stick skillet over medium heat. Add the pancetta and cook, stirring occasionally, until browned and crispy. Remove the pancetta from the skillet, reserving the rendered fat. Proceed to the next step using the same skillet with pancetta fat.
Heat the skillet over medium heat. Add diced onion and sauté until translucent.
Stir in the garlic and cook for another minute, then toss in the chopped asparagus, salt and pepper, and cook for about 5 minutes, or until tender. Remove from heat and set aside.
In a bowl, mix ricotta cheese with cooked pancetta and asparagus mixture. Add olive oil and other salt and pepper to taste.
In a small bowl, mix together the chopped tomatoes, torn basil leaves, and half of the Parmesan cheese until well combined.
Preheat your oven to 180 °C (356 °F) and lightly grease a 23×33 cm (9×13 inch) baking dish with a thin coating of olive oil or non-stick cooking spray.
Begin by spreading a thin layer of tomato mixture at the bottom. Place a layer of lasagna sheets over the tomato mixture and spread a layer of half of the ricotta mixture over the pasta, followed by 1/3 of shredded mozzarella and 1 tablespoon grated parmesan.
Repeat with pasta, remaining ricotta mixture, 1/3 mozzarella and Parmesan, and finishing with a layer of lasagna sheets topped with tomato mixture, the remaining mozzarella and a generous sprinkle of Parmigiano Reggiano.
Cover the dish with foil and bake for 25 minutes. Then, remove the foil and bake for an additional 10–15 minutes, or until the top is golden and bubbly.
Remove from the oven and let the lasagna cool for a few minutes before serving.