Easy Vegetarian Spinach Lasagna

Preheat the oven to 400 degrees F (200 degrees C). Spray a 1 1/2-quart casserole dish with cooking spray. Set aside.

Bring a large pot of lightly salted water to a boil. Place spinach in the water and boil until wilted and tender, about 2 minutes. Remove spinach with a slotted spoon, pressing out excess water. Set aside.

Cook lasagna in the same boiling water, stirring occasionally, until cooked through but firm to the bite, about 8 minutes. Drain.