This is another classic Lilith meal, super quick and easy to throw together.
Basically I cooked the mushrooms and spinach in a skillet with some olive oil first. And I pre cooked the burgers in the microwave for a minute.
Set the oven to 350.
Assemble the burgers, then marinara, then spinach and mushrooms, then cheese. Bake for 5 minutes. (I made some onion rings with this so was able to cook them at the same time).