In a medium saucepan over medium heat, melt the Unsalted Butter (3 tablespoon). Once melted, stir in All-Purpose Flour (3 tablespoon) and cook for 1 minute, stirring often as you don't want it to brown.
Add 2% Reduced Fat Milk (1 cup), whisking constantly until mixture comes to a boil and is smooth.
Add 2% Reduced Fat Milk (1 cup), whisking until mixture again reaches a boil.
Stir in 2% Reduced Fat Milk (1 cup) and whisk until smooth. Reduce heat and cook for 5 minutes, whisking often to prevent burning.
Remove from heat and stir in both the Gruyère Cheese (1 cup) and Parmesan Cheese (1/4 cup). Add Fresh Sage (2 tablespoon), Salt (1 teaspoon), and Ground Black Pepper (1/2 teaspoon). Stir until cheese has melted and mixture is smooth.
Cover with plastic wrap directly on the surface of sauce and set aside until ready with the remainder of dish, or you can refrigerate at this point and use later.
Rehydrate Dried Mushrooms (1 ounce) as per package directions. Allow to cool slightly and coarsely chop.
Heat a large skillet over medium heat and add Olive Oil (1 tablespoon). Sauté White Onion (1/2 cup) for 2 to 3 minutes until soft. Add Garlic (3 clove) and continue to cook for 1 minute.
Add both wild and Cremini Mushroom (8 ounce) to the pan, and cook until soft and most of the liquid has evaporated. Stir in Worcestershire Sauce (2 tablespoon) and cook for 2-3 minutes until mixture is dry again. Remove from heat and allow to cool slightly before proceeding.
In a medium-size bowl, stir together Ricotta Cheese (3/4 cup), Grated Parmesan Cheese (1/2 cup), Egg (1), Fresh Sage (1 tablespoon), Salt (1/2 teaspoon), and Ground Black Pepper (1/4 teaspoon).
When mushroom mixture has cooled, stir into cheese mixture. Set aside.
Preheat oven to 350 degrees F (176 degrees C).
Spray an approximate 11"x7" shallow casserole or lasagna pan with non stick spray.
If béchamel was chilled, warm over low heat before proceeding. Spread 1/2 cup sauce evenly over the bottom of prepared pan. Top with Lasagna Sheets (360 gram), try not to overlap them too much.
Spread 1/3 of mushroom mixture evenly over lasagna sheet. Ladle 1/2 cup sauce over layer and sprinkle with a 2 to 3 tablespoons of Mozzarella Cheese (1 1/2 cup). Repeat layer two more times, pasta, 1/3 mushroom mixture, 1/2 cup sauce, sprinkle of cheese.
Top with last layer of lasagna noodles and 1/2 cup sauce, and remainder of mozzarella cheese. Cover with foil and bake 45-60 minutes, or an instant-read thermometer reads 170 degrees F (75 degrees C).
Remove foil and broil for 2-3 minutes until cheese is melty and golden. Remove from oven and allow to rest for 10-15 minutes before cutting and serving. Enjoy!