Cut mushrooms into thin slices.
Coarsely chop spinach.
Stem and coarsely chop oregano.
Break lasagna noodles into large chunks.
Cook the Noodles
Place noodles in boiling water and cook until al dente, 7-9 minutes.
Drain noodles in a colander. Set aside.
While noodles cook, make sauce.
Make the Sauce
Place a large non-stick pan over medium-high heat and add 2 tsp. olive oil. You may also use a cast iron skillet.
Add mushrooms and ¼ tsp. salt to hot pan and stir occasionally until softened and lightly browned, 7-8 minutes.
Add garlic, spinach, and sauce and stir often until spinach is wilted, 1-2 minutes.
Remove from burner.
Combine with Pasta
Stir in cooked noodles. Top with mozzarella and return to medium heat. Cover and cook undisturbed until melted, 3-4 minutes.
Remove from burner. Garnish with oregano and Parmesan.