Step 1

Arrange a rack in the middle of the oven and heat to 400°F. Coat a 9×13-inch baking dish with olive oil or cooking spray.

Step 2

Place the marinara sauce and water in the baking dish and stir to combine. Add the orzo and spinach and stir to combine. Dollop the ricotta and sprinkle the cubed mozzarella evenly over the mixture and gently stir, keeping a few streaks of ricotta here and there. Spread the mixture into an even layer.

Step 3

Cover the dish tightly with aluminum foil. Bake until the pasta is almost tender, about 30 minutes. Uncover and bake until the top is browned and has crisped up a bit, about 10 minutes more. Let cool for 5 to 10 minutes before serving.