Preheat the oven to 375°F. In a 9 x 13-inch casserole dish spread a first layer of Portobello Mushroom Sauce and cover it with Lasagna sheets.
Top the Lasagna sheets with a layer of béchamel sauce, evenly distributed, then top with Portobello Mushroom Sauce and shaved truffle. Repeat the steps to form four other layers.
Top the last layer with béchamel sauce, Portobello Mushroom Sauce and thinly shave the remaining truffles. Bake until golden brown for around 20 minutes, slice and serve.