Slice zucchini into strips using your mandolin. I use this one on the thin setting. It would be really tough to do this by hand, but if you have magical knife skills, I’m sure you could manage. You might even be able to use a vegetable peeler to make the strips, but I haven’t tested that out.

Place zucchini strips on a large sheet pan, sprinkling each layer with salt as you cut them. Let sit for at least 30 minutes. This is crucial, as it draws out excess moisture from the zucchini (and seasons it!).

Meanwhile, start preparing the meat sauce. Begin by finely chopping the mushrooms in the food processor (or by hand).

Brown ground beef in a cast iron skillet. Remove meat from pan, leaving drippings behind.

Brown the mushrooms in beef drippings on high heat, being sure most of moisture has evaporated. Reduce heat to medium and add onions and garlic to the pan to brown. You may need to add more fat (I use a combo of butter and olive oil). Finally, add marinara sauce to the pan to heat through and thicken slightly. Add beef back to the pan and remove from the heat.

Next, make the cheese filling. Combine all ingredients in the food processor and whiz until combined.

Dry zucchini slices by laying out on a clean kitchen towel or paper towels. Blot dry before assembling the lasagna.

Spread a thin layer of meat sauce on the bottom of a 9x13 inch glass pan. Then begin assembling by alternating layers of zucchini (your “noodles”), meat sauce, cheese filling, and finishing with a layer of parmesan and mozzarella cheese.

Bake uncovered in a 375 degree for 45-60 minutes, until the top is brown and bubbly. Let stand 20 minutes before serving (if you can handle it!).