Start by preheating your oven and carefully slicing the squash in half lengthwise. Scoop out the seeds and brush the inside with olive oil, then season with salt and pepper. Place the halves cut-side down on a baking sheet and roast until tender.
While the squash roasts, heat a skillet over medium heat and cook the sausage until browned. Add minced garlic and let it cook briefly until fragrant. Stir in marinara sauce and oregano, then simmer for a few minutes to develop flavor.
In a bowl, mix together ricotta cheese, egg, and a pinch of salt and pepper. This mixture should be smooth and creamy. The egg helps it set nicely when baked, giving you that classic lasagna texture.
Once the squash is done roasting, let it cool slightly. Use a fork to gently scrape the flesh into spaghetti-like strands while keeping them inside the shell. This creates the “noodle” base for your lasagna.
Layer the sausage sauce over the squash strands, followed by spoonfuls of the ricotta mixture. Sprinkle mozzarella and Parmesan cheese generously on top. Repeat layers if there’s room, ending with cheese.
Place the filled squash halves back into the oven and bake until the cheese is melted and bubbly. The tops should be slightly golden and irresistible.
Remove from the oven and let them cool for a few minutes. Finish with freshly chopped basil for a burst of flavor and color before serving.