On the surface, this looks just like a traditional lasagna, a blanket of brown-edged mozzarella tucked into the red sauce. But cut yourself a slice, and you’ll see the difference. Separating the creamy ricotta layers are thick, yellow stripes of polenta speckled green with spinach. The polenta offers a sweet contrast to the savory tomato sauce, along with a pleasingly nubby texture that’s firm but not chewy.
Be sure to get a good brand of marinara sauce, preferably one with chunky bits of tomato, for the deepest flavor.
• 4 tablespoons unsalted butter
• 1 tablespoon plus 1/2 teaspoon kosher salt
• 2 cups polenta
• 5 cups baby spinach
• 2 cups grated Parmesan
• 1 2/3 cups whole-milk ricotta
• 3 tablespoons parsley, finely chopped
• 2 tablespoons basil, chopped
• 1 large egg
• 1/2 teaspoon black pepper
• 1/8 teaspoon grated fresh nutmeg
• 3 cups marinara sauce
• Large pinch red pepper flakes, 1 pinch dried oregano, 1 grated garlic clove, drizzle of extra-virgin olive oil (all optional)
• 4 cups shredded mozzarella
Heat oven to 425 degrees and butter an 13-by-18-inch rimmed baking sheet pan. Grease a rubber spatula with butter.
In a large pot, bring 6 cups water and 1 tablespoon salt to a boil over high heat. Reduce heat to medium, then slowly pour in polenta, whisking constantly. Cook until polenta thickens, 8-12 minutes. Whisk in 4 tablespoons butter until melted. Whisk in spinach until wilted. Remove from heat and mix in 1 cup grated Parmesan.
Scrape polenta onto the baking sheet. Using the greased rubber spatula, spread the mixture into a thin layer to cover the entire pan. Sprinkle 1/2 cup grated Parmesan on top. Bake until polenta is firm, 12-18 minutes. Let cool until completely cooled, about 1-1 1/2 hours.
When ready to bake the lasagna, heat oven to 400 degrees. Butter a 9-by-13-inch baking dish.
In a bowl, mix ricotta, parsley, basil, egg, black pepper, nutmeg and the remaining 1/2 teaspoon salt. Mix until well combined and set aside.
Taste the marinara sauce. If it needs some zip, stir in any of the optional ingredients.
Assemble the lasagna: Using a knife or pizza cutter, cut cooled polenta in half widthwise, creating 2 pieces roughly 9 by 13 inches each. Using a large spatula, gently place one half in prepared baking dish.
Spread about half the ricotta mixture in an even layer on top of polenta.
Pour about half of marinara sauce on top of ricotta, sprinkle with about half of the shredded mozzarella. Repeat with remaining polenta, ricotta, marinara and mozzarella. Once assembled, sprinkle the remaining 1/2 cup Parmesan on top.
Place baking dish on top of a rimmed sheet pan in case the lasagna bubbles over. Bake until cheese melts. If you like, you can broil lasagna for 2 minutes after baking until cheese starts to bubble and develop brown spots.
Remove from oven and let lasagna stand for about 15 minutes to firm up before serving. Leftovers can be refrigerated for up to 1 week or frozen for up to 3 months.
Total time: 2 1/2 hours; serves 8-12.