Preheat oven to 375 F (190 C)
Bring a large pot of lightly salted water to a boil. Cook lasagna noodles in boiling water for 8 to 10 minutes or as per instructions on the package. Drain the noodles and rinse with cold water
In a medium size mixing bowl, combine ricotta cheese with egg, dill, parsley and 1 teaspoon salt. Set aside
Preheat a large skillet with 2 tablespoons butter or oil. Add onions and saute over medium heat for 9-10 minutes, until translucent and golden brown. Add 1/4 tsp salt and 1/4 tsp black pepper when almost done. Transfer into a bowl
Using the same skillet, saute oyster mushrooms with 2 tablespoons butter or oil over high heat for 5-6 minutes
Turn heat to medium, add 1/2 teaspoon salt and 1/4 teaspoon ground pepper, and saute for another 3 minutes
Add onions to mushrooms and continue sauteing over medium heat for another 2-3 minutes. Remove from heat and transfer to a bowl
To assemble lasagna, spread about 1 tablespoon of ricotta cheese filling on the bottom of a 8 x 8 inch baking dish. Arrange 3 noodles on the bottom of the pan (you will need to cut them to needed length).
Spread half of the ricotta cheese filing over noodles. Top with half of oyster mushroom and onion mix, followed by 1 cup mozzarella cheese and 2 tablespoons grated Parmesan cheese.
Repeat another layer
Cover with foil, ensuring that foil does not touch the top of the lasagna
Bake in preheated oven for 25 minutes. Remove foil and bake additional 20 minutes
Cool for 10-15 minutes and serve