Step 1

Preheat the oven to 375°F.

Step 2

In a medium bowl, mix together the ricotta, feta, garlic, basil, sage, red pepper flakes and a few generous pinches of salt and pepper.

Step 3

Lightly grease an 8x8 or similar size baking pan with olive oil. (Pictured is a 7x10 inch pan) Spread the marinara sauce over the bottom of the baking dish and top with the first layer of sweet potato slices. Spread with half of the ricotta cheese mixture and add a layer of 1 cup baby spinach. Add the next sweet potato layer, the remaining ricotta cheese, and the remaining spinach. Top with the last layer of sweet potatoes, the shredded mozzarella, and the Parmigiano cheese.

Step 4

Bake for 35 minutes, uncovered. If cheese starts browning too much, cover the pan with a sheet of aluminum foil. Add the remaining fresh sage during the last minute of baking time.

Step 5

Remove from the oven and let sit for 15 minutes before slicing. Sprinkle with parsley, if using.