Preheat the oven to 375 degrees F.
For the tomato sauce: Heat a large, deep skillet over medium-high heat and add the olive oil. Add the lamb, onions and peppers, and cook until the lamb is browned and the vegetables are softened, about 10 minutes. Stir in the tomato paste, and then add the tomato sauce, wine, chicken stock, rosemary, thyme, herbs de Provence and nutmeg. Season with salt and pepper. Simmer while you prepare the cheese filling.
For the cheese filling: In a large bowl, combine the ricotta with the mozzarella and pecorino. Add the egg and yolks and stir well to combine. Stir in the spinach and season with salt and pepper.
To assemble: Remove the sauce from the heat and spread some on the bottom of a 9-by-13-inch baking dish. Lay 2 pasta sheets over the sauce, top with some cheese filling and then some more sauce. Layer on 2 more pasta sheets and repeat until all of the cheese filling and sauce are used, finishing with the sauce. (You may or may not use all of the pasta sheets.) Sprinkle the top with some grated pecorino.
Cover the lasagna with foil and bake in the oven for about 1 hour. Then uncover and bake until the pasta is cooked and the cheese on top is golden and bubbly, about 20 minutes more. Let sit a few minutes before slicing and serving.
This recipe was created by a contestant during a cooking competition. The Food Network Kitchens have not tested it for home use, therefore, we cannot make any representation as to the results.