2 tablespoons extra virgin olive oil (EVOO)
2 1/2 pounds sweet Italian chicken sausage, removed from casing
1 pound button mushrooms, sliced
Salt and freshly ground black pepper
4 tablespoons butter
4 tablespoons flour
2 cups milk
2 cups chicken stock
A generous dash fresh nutmeg
1 box oven-ready lasagna noodles
4 cups shredded Italian four-cheese blend
Pre-heat the oven to 375ºF.
Place a large skillet over medium high heat with 2 tablespoons EVOO, about two turns of the pan. Add the sausage to the pan and cook, breaking it up with a spoon, until the meat is crumbled and golden brown, about 10 minutes.
Add the mushrooms to the pan and cook until golden brown, 5-6 minutes. Season the mixture with salt and freshly ground black pepper and reserve.
While the meat is browning up, place a large saucepot over medium heat and melt the butter. Sprinkle the flour over the butter and cook it for about 1 minute. Whisk in the milk and chicken stock and bring the sauce up to a bubble. Add in the nutmeg and season it with salt and freshly ground black pepper, then simmer until the sauce thickens, 3-4 minutes.
Assemble the lasagna by ladling a small amount (about 1/2 cup, just eyeball it) of the sauce into the bottom of a 13-inch x 9-inch baking dish. Lay three of the lasagna noodles over the sauce and top them with about 1/3 of the meat-mushroom mixture. Top with about 1 cup of the sauce and about 1 cup of the shredded cheese (about 2 generous handfuls). Make two more layers of the lasagna by laying down three lasagna noodles, about 1/3 of the meat-mushroom mixture, 1 cup of the sauce and about 1 cup shredded cheese for each layer. Top the lasagna off with the last three noodles, the remaining sauce, and the remaining shredded cheese.
Cover the pan with aluminum foil and bake the lasagna for 30 minutes. Remove the foil from the baking dish and bake another 15 minutes until the cheese is melted and the sauce is bubbly.