Preheat the oven to 400 degrees Fahrenheit

Use a vegetable peeler to peel the skin off of your butternut squash. Cut off the tip and tail, then slice it into ¼ to ½ inch rounds, starting at the tip end of the squash. Once you get to the tail end, you can slice the remainder of the squash in half to scoop out the seeds and insides. Continue slicing the squash into thin U shapes. You’ll be using the whole squash!

Heat a large thick-bottomed pot such as a Dutch oven over medium-high heat and add the ground beef. There is no need to add oil here unless your pan has a tendency to stick. Use a spatula to break the beef into smaller chunks and brown the beef until it is almost fully cooked through. Add in the pasta sauce and bring the mixture to a full but controlled boil. Reduce the heat if needed and continue cooking the sauce, stirring occasionally, for 5 minutes. Taste the sauce for flavor and add sea salt and black pepper to your personal taste.

Spray a large casserole dish (I use a 13” x 9” casserole dish) with cooking spray. Coat the bottom of the pan with a light layer of sauce.

Place a layer of butternut squash slices on the bottom of the casserole dish in a single layer without any overlapping. Spread ⅓ of the meat sauce over the sliced butternut squash and spread it evenly. Sprinkle ⅓ of the grated mozzarella cheese over the sauce layer.

Create two additional layers just like this, using the rest of the butternut squash slices and the cheese.

Cover the baking dish in aluminum foil and bake on the center rack of the oven for 50-60 minutes, until the butternut squash has reached your desired level of tenderness.

Allow the lasagna to cool for 15 minutes before slicing and serving. Serve with any side dishes you enjoy, like a side salad, roasted vegetables, or bread and butter.