Ingredients

• 1 pound mushrooms (cremini or button), finely chopped
• 1 cup brown lentils, dried, rinsed
• 3 tablespoon olive oil
• 1 yellow onion, diced
• 4 clove garlic, minced
• 2 tablespoon tomato paste
• 1 crushed San Marzano tomatoes
• 1 cup whole milk
• 3 tablespoon unsalted butter
• 3 tablespoon all-purpose flour
• 0.5 teaspoon ground nutmeg
• 1 teaspoon kosher salt
• 0.5 teaspoon black pepper, ground
• 1 teaspoon dried oregano
• 1 teaspoon dried basil
• 1 pound lasagna noodles
• 2 cup ricotta cheese
• 2 cup mozzarella cheese, shredded
• 0.5 cup Parmesan cheese, grated
• 1 large egg

Steps

1. Rinse the brown lentils in a colander under cold water and set aside.
2. Bring a large pot of salted water to a boil. Add lasagna noodles and cook according to package directions until al dente, about 9-10 minutes.
3. Drain noodles in a colander, rinse lightly with cold water, lay them flat on parchment paper to prevent sticking, and set aside.
4. While noodles cook, heat 3 tablespoons of olive oil in a large saucepan over medium heat.
5. Add diced onion and cook, stirring occasionally, until softened, about 5 minutes.
6. Stir in minced garlic and cook for 1 minute until fragrant.
7. Add finely chopped mushrooms to the pan and cook, stirring occasionally, until they release their moisture and begin to brown, about 8-10 minutes.
8. Stir in tomato paste and cook for 2 minutes, stirring constantly.
9. Add the rinsed lentils, crushed San Marzano tomatoes, dried oregano, dried basil, 0.5 teaspoon kosher salt, and 1/4 teaspoon black pepper to the pan.
10. Bring the ragù to a gentle simmer and cook uncovered for 20-25 minutes, stirring occasionally, until lentils are tender and sauce has thickened.
11. While the ragù simmers, prepare the béchamel sauce: melt 3 tablespoons unsalted butter in a medium saucepan over medium heat.
12. Add 3 tablespoons all-purpose flour and whisk constantly for 2 minutes to cook the raw flour taste out of the roux.
13. Slowly pour in 1 cup whole milk while whisking constantly to avoid lumps.
14. Continue cooking and whisking until the béchamel thickens enough to coat the back of a spoon, about 5-7 minutes.
15. Remove béchamel from heat and whisk in 1/2 teaspoon ground nutmeg, remaining 0.5 teaspoon kosher salt, and remaining 1/4 teaspoon black pepper.
16. In a small bowl, combine 2 cups ricotta cheese, 1 large egg, 1 cup mozzarella cheese, and 1/4 cup Parmesan cheese.
17. Preheat oven to 375°F.
18. Spread a thin layer of mushroom-lentil ragù (about 1 cup) on the bottom of a 9x13 baking pan.
19. Arrange a layer of lasagna noodles (about 4 noodles, slightly overlapping) over the ragù.
20. Spread one-third of the ricotta mixture evenly over the noodles.
21. Spread one-third of the remaining ragù over the ricotta layer.
22. Drizzle one-quarter of the béchamel over the ragù layer.
23. Repeat the layers: noodles, ricotta mixture, ragù, and béchamel, three more times, ensuring the final layer is noodles topped with béchamel.
24. Sprinkle the remaining 1 cup mozzarella cheese and 1/4 cup Parmesan cheese evenly over the top.
25. Cover the baking pan with aluminum foil (spray the underside lightly with cooking spray to prevent sticking).
26. Bake covered for 25 minutes.
27. Remove foil and continue baking until the top is golden brown and bubbly at the edges, about 15-20 minutes.
28. Remove from oven and let rest for 10 minutes before cutting and serving.
29. Cut into 12 pieces (3 rows × 4 columns) and serve hot.