Preheat your oven to 375°F (190°C).
Cook the lasagna noodles according to package instructions; drain and set aside.
In a bowl, mix ricotta cheese, garlic powder, oregano, salt, and pepper.
Spread a layer of béchamel sauce in the bottom of a baking dish.
Place a layer of lasagna noodles over the sauce.
Spread half of the ricotta mixture over the noodles.
Add a layer of spinach or mushrooms, followed by a layer of mozzarella.
Repeat the process, ending with a layer of noodles and béchamel sauce.
Sprinkle Parmesan cheese on top.
Bake for 45 minutes or until golden and bubbly.