Substitute 1 pkg. (300 g) frozen chopped spinach for the browned ground beef. Thaw spinach; squeeze out excess liquid. Prepare as directed, covering each ricotta layer with 1/3 of the spinach.
Adding water to the sauce helps cook traditional noodles during baking, so you don't have to cook them beforehand. This saves you 15 to 20 minutes of prep time.
Placing a layer of sauce under the first layer of noodles will help prevent the noodles from sticking to the bottom of the baking dish.