Step 1

Preheat oven to 400 degrees F. Coat an 11- x 7-inch baking dish with cooking spray. Prepare pasta according to package directions; drain.

Step 2

Heat oil in a large skillet over medium-high. Add mushrooms; cook, stirring often, until lightly browned, 5 to 6 minutes. Add garlic; cook, stirring occasionally, until mushrooms are soft, 3 to 4 minutes. Add spinach; cook, stirring constantly, until wilted and liquid evaporates, 4 to 5 minutes. Remove from heat.

Step 3

Stir together pasta, mushroom mixture and marinara in a large bowl. Spoon mixture evenly into prepared baking dish; sprinkle evenly with cheese. Bake in preheated oven until cheese is bubbly and lightly browned, 25 to 30 minutes.