Eggplant Cannelloni

To make the béchamel sauce, in a saucepan over medium heat, warm the milk until it begins to steam, about 5 minutes. Remove from the heat and add the nutmeg. Keep hot.

In a heavy, nonstick saucepan over medium heat, warm the canola oil. Using a wooden spoon, stir in the flour. Then, using a mashing motion, stir constantly until the flour mixture begins to become fluffy and looks shiny, 3 to 4 minutes. Cook for 30 seconds more, taking care not to let the flour color.

While whisking vigorously, pour in 1/2 cup of the hot milk. When the mixture is as smooth as you can get it, pour in the remaining milk while whisking constantly. Cook over medium heat until the lumps have dissolved and the sauce comes to a boil. Then, reducing the heat as needed to prevent scorching, cook, stirring often, until the sauce has the consistency of light whipping cream, about 5 minutes. Add the salt and pepper.

Pour the sauce into a bowl, passing it through a fine-mesh sieve if lumps are visible. Use immediately, or cover the hot sauce with a piece of plastic wrap, pressing it against the surface to prevent a skin from forming. Set the sauce aside to cool, then refrigerate for up to 2 days before using.

Position racks in the upper third and lower third of an oven and preheat to 375°F. Brush 2 large baking sheets with 2 tsp. of the olive oil.

Cut off the stem end of the eggplant. Standing it upright on the cut end, and using a serrated knife or very sharp, thin-bladed knife, cut the eggplant vertically into slices 1/4 inch thick. Discard the 2 outer slices, which are mostly skin. You will have 12 slices. Arrange 6 eggplant slices on each baking sheet and brush with 1 1/2 tsp. of the olive oil. Turn the slices over and brush with the remaining 1 1/2 tsp. olive oil. Bake the eggplant until it starts to soften, about 10 minutes. Turn the eggplant slices over and return the baking sheets to the oven, putting them on opposite racks. Bake until the eggplant slices are flexible at the neck end and still hold together at the wide end, 6 to 10 minutes more. Using a spatula, transfer the slices to a plate and set aside. Reduce the oven temperature to 350°F.

To make the filling, in a nonstick fry pan over medium-high heat, warm the 1 tsp. olive oil. Add the onion and sauté until it starts to brown, about 5 minutes. Mix in the mushrooms, cook until they release their liquid and then continue to cook, stirring occasionally, until they are dry and start to brown, 6 to 7 minutes total. Stir in the turkey, breaking it up with a wooden spoon. When the meat loses its pink color, after 4 to 5 minutes, transfer the mixture to a bowl. Mix in the ricotta and prosciutto, then stir in the bread crumbs and the pepper just until the ingredients are evenly distributed; be careful not to overmix the filling or it will become gluey.

Spread 1 cup of the béchamel sauce to cover the bottom of a shallow 1-quart baking dish. Lay an eggplant slice, with the wide end closest to you, on a work surface, and place 1/4 cup of the filling on the wide end. Lift the slice and roll away from you, pressing lightly so the filling spreads the whole width of the slice and enclosing the filling completely. Place in the prepared baking dish. Repeat with the remaining eggplant slices, forming 2 rows in the dish. You may not need all of the filling. Pour the remaining béchamel sauce evenly over the eggplant. Sprinkle the Parmigiano-Reggiano cheese on top. Cover the baking dish with aluminum foil.

Bake until the eggplant is soft and a knife inserted into the center of a roll is hot to the touch when removed, 1 to 1 1/4 hours. Remove the cannelloni from the oven and let rest for 15 minutes. Divide among warmed plates and serve immediately. Serves 6.