4 cups whole milk
1 – 2” piece of rosemary
2 teaspoons minced garlic
1 1/2 sticks unsalted butter, divided
1/2 cup all-purpose flour
1 1/2 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
1/2teaspoon ground nutmeg
1 1/2 pounds mixed mushrooms – such as cremini, oyster, piopini, shitake, etc.
2-3 tablespoons Safflower oil
2 tablespoons butter
1 lb no-boil lasagna noodles
3/4 cup freshly grated parmesan
1 cup fresh ricotta
Preheat your oven to 375F.
Bring the milk, rosemary, and garlic to simmer in a saucepan, set it aside. Melt 1 stick butter in a large saucepan, letting it foam and brown slightly. Add the flour, and stir constantly for one minute. Remove the rosemary stem from the milk, and pour the milk into the butter/flour mixture slowly; stirring until combined. Add the kosher salt, pepper, and nutmeg. Cook over medium-low heat, stirring or whisking frequently, for 3 to 5 minutes, or until thickened. Set aside.
Slice all mushrooms to uniform thickness – about ¼ inch slices. Heat half the oil and one tablespoon of butter over medium heat in heavy bottomed sauté pan. Brown half the mushrooms with a couple pinches of salt for about 5 minutes, stirring occasionally until they are tender and release some of their juices. Repeat with the other half of the mushrooms, oil and butter.
Spread a layer of béchamel in the bottom of a 9 x 13 baking dish. Arrange a layer of noodles on top, then more sauce, 1/3 of the mushrooms, ¼ cup grated parmesan, and about ½ of the ricotta. Repeat with more sauce, noodles, mushrooms and cheeses. Finish with the final layer of noodles, mushrooms, remaining sauce and last ¼ cup of parmesan. Bake for 45 minutes, or until top is browned and the sauce is bubbly.