Now, slice the sweet potatoes very thin, approx. ⅛ - 1/16 of an inch. (You can either use a mandolin or a sharp knife.) The more uniform the better so they cook evenly.
In a medium mixing bowl, combine the cottage cheese with the egg and and finely chopped italian parsley. Mix well and then set aside.
Heat 1 tbsp. olive oil over medium-high heat in a large skillet. Once hot, add the lean ground pork, dried oregano, dried thyme, kosher salt, and ground black pepper. Cook this until it becomes well-browned, which should take 6-8 minutes, stirring frequently.
Once the meat is well-browned, remove it from the pan and set aside. Reserve about 1 tablespoon of the rendered fat from the pork. If you have more than that, you can discard the rest.
Add diced yellow onion and cook it over medium-high heat until it starts to become tender.
Then, add in the cremini mushrooms and cook for an additional 4-6 minutes, or until the mushrooms start to become tender.
Add in minced garlic and cook for one more minute, until the garlic becomes fragrant.
Return the cooked pork and add the tomato sauce into the pan and stir to combine. Once this is heated through, remove from the heat.
To assemble the lasagna, use a 9x16 casserole dish and create the first layer with the sweet potato slices. Make sure to overlap each slice to create an even layer.
Pour out half the meat sauce over the sweet potato slices and spread out evenly.
Pour out half of the cottage cheese mixture over the meat sauce and spread evenly. (It’s okay if it doesn’t look perfect - it will still be super tasty.)
Repeat these three steps with another layer of sweet potato slices, meat sauce, and then the cottage cheese.
Top with a thin layer of sliced fresh mozzarella and then cover with tin foil.
Place in the oven bake for 30-40 minutes, or until the sweet potato slices are almost fully tender. If you have thicker slices it may take longer.