Preheat the oven to 350°F. Bring a large pot of salted water to a boil.

Once the water is boiling, add the olive oil to the pot. Add the noodles and cook, stirring occasionally, for 8 to 10 minutes, or until al dente. Drain well. Cut or tear 2 of the noodles in half widthwise.

Meanwhile, drain the spinach well by squeezing it in a clean, lint-free dish towel until all the excess moisture is removed — then keep squeezing a bit more to be sure. In a medium bowl, stir together the ricotta, egg whites, 3 tablespoons of the Parmesan, parsley, and garlic powder until well combined. Stir in the drained spinach. Season with salt and pepper.

To assemble, spread 1/2 cup marinara evenly over the bottom of a 9" x 13" glass or ceramic baking dish. Lay 3-1/2 noodles evenly across the bottom in a single layer. Dollop one-third of the ricotta mixture over the noodles and spread into an even layer. Top with 1/2 cup of the remaining sauce, then sprinkle one-quarter of the mozzarella evenly over the sauce. Repeat this layering (noodles, ricotta mixture, sauce, mozzarella) two more times.

For the final layer, top with the last of the noodles. Spread the remaining sauce evenly over the noodles. Sprinkle with the remaining mozzarella, then the remaining Parmesan.

Cover with foil and bake for 30 minutes. Uncover and bake 5 to 10 minutes longer, until the cheese is melted and the lasagna is hot throughout. Cool 5 minutes, then cut into 8 squares and serve.