Butter or spray a 9x13x4-inch deep baking dish and set aside.

Preheat oven to 375 degrees F.

Bring a large pot of water to a boil and once boiling, add a teaspoon of kosher salt and plunge in the lasagna noodles. Only boil them for five minutes, then drain and run under cold water. They will still be stiff and not cooked but will be pliable enough to use. Let sit in the cold water until you are ready to use them.

In a medium saucepan, heat milk to hot but do not boil.

In a medium pot or large saucepan, melt two tablespoons of the butter over medium high heat and add the mushrooms and cook for about five minutes until browned. Remove to a bowl.

Add the remaining 4 tablespoons of butter and add the onions and cook for four minutes, stirring often.

Add garlic and cook for one more minute.

Lower heat to medium low and add the flour and cook, stirring often for three minutes.

Start whisking the hot milk into the butter and flour mixture, one third at a time, whisking each addition until smooth. The first third will be thick like paste, the second addition smoother, and the final addition will make a nice creamy sauce. Move the heat to low.

Add ½ teaspoon of the salt (assuming your ham is not too salty), half a teaspoon of white pepper, the dry mustard and nutmeg and whisk to combine then remove from heat.

Spread one cup of the white sauce in the bottom of the prepared casserole dish or baking pan.

Add the cooked mushrooms to the remaining white sauce and set aside.

In a large bowl, mix half of ham, all of the cottage cheese, the two eggs and one egg yolk, all of the Parmesan cheese, half of the Swiss, the parsley, the rest of the white pepper (1/2 teaspoon) and a half teaspoon of kosher salt as long as your ham is not too salty, otherwise omit the salt.

Start building the lasagna.

Drain then lay out four strips of noodles over the sauced pan bottom, overlapping to fit.

Top that with half of the cottage cheese mixture then add four more noodles.

Spread 1/3 of the white sauce over the noodles and add half of the remaining cut up ham and half of the remaining shredded Swiss.

Top with four more noodles, the rest of the cottage cheese mixture and three or four more noodles (saving four noodles for top).

Add another third of sauce, rest of ham, rest of Swiss and top with the remaining noodles.

Spread the remaining sauce over the top and sprinkle on the shredded mozzarella cheese.

Bake for 40 minutes, remove and let sit 20 minutes before cutting 3 rows by 4 rows into 12 portions.