Preheat the oven to 350°F (175°C). Lightly spray a 9x13-inch baking dish with nonstick spray if desired.
In a large bowl combine the marinara sauce and 1 cup water; stir to loosen any sauce left in the jar.
Add 2 cups of the shredded mozzarella, 3/4 cup of the grated Parmesan, the ricotta, kosher salt, and black pepper to the sauce mixture and stir until fully combined.
Break the lasagna noodles into ~3-inch pieces and add them to the bowl; stir with a sturdy spoon or spatula until all noodles are thoroughly coated in the sauce mixture.
Pour the mixture into the prepared 9x13-inch pan and spread into an even layer.
Sprinkle the remaining 1 cup mozzarella and remaining 1/4 cup Parmesan evenly over the top.
Cover the dish tightly with foil and bake for 60 minutes.
Remove the foil, drizzle the olive oil evenly over the top, and return to the oven uncovered for 15 minutes, until the cheese is bubbly and lightly golden.
Let the lasagna rest a few minutes, sprinkle with minced parsley if using, then cut into squares and serve.