Preheat oven to 350º. Bring a large pot of salted boiling water to a boil and cook lasagna noodles until al dente. Drain.

In a large skillet over medium heat, heat oil. Add onion and garlic and season with salt, pepper, and red pepper flakes. Cook until onions are soft, about 5 minutes. Add spinach and cook until wilted. Stir in lemon zest and remove from heat.

In a large bowl, stir ricotta, egg, and 1/2 cup Parmesan until combined then season with salt and pepper.

Spread ricotta mixture onto one side of each lasagna noodle. Top with marinara and cooked spinach, then sprinkle with mozzarella and roll up tightly.

In a large deep baking dish, spoon a layer of marinara on bottom of dish. Add the roll-ups and spoon more sauce onto each roll-up. Sprinkle more mozzarella and Parmesan over each roll up. Bake until bubbly and melted, about 20 minutes.

Garnish with parsley before serving.

Recipe and image courtesy of Best Lasagna Roll-Ups Recipe - How to Make Lasagna Roll-Ups (delish.com)