In a big pot, boil water and cook off lasagne sheets. When done, remove sheets with tongs and lay on wax paper in layers, to prevent them from sticking together.
Brown your sausage, hamburger and half of your garlic in a large pot over medium-high heat, with fennel, mustard, salt, pepper, and red pepper flakes. After it's been cooking for about 5 minutes, add your vermouth, and continue to cook until all of the meat is browned.
In another pot, over medium heat, start you carrots, onion, salt, and pepper with olive oil. After about 10 minutes, add your tomatoes and spices, then green and red peppers. After about 10 more mintes, add in your red wine, and your cooked meat from the other pot. Stir it all together, and reduce heat to low.
In a sauté pan, cook your mushrooms with salt and pepper and olive oil over medium heat. As they start to brown and soften, add in your spinach, and red wine. The spinach will wilt down and become cooked fairly quickly. When that's happened, reduce the heat to low, and continue to cook off the wine (about 5 minutes). Turn off the heat.
Now, with a rubber spatula, mix ricotta cheese and parmesean cheese with oregano, salt, and pepper in a bowl.
Here's a great place to put things into a holding pattern and grab yourself a cigarette, another beer, whatever.
OK - now it's time to assemble it. Fine a good sized pan, and with a ladel put a layer of sauce in the bottom, followed by some of the spinach and mushroom mixture. Then a layer of pasta, a layer of your cheese mixture and sprinkle some of your walnuts over that, a layer of pasta, a layer of sauce and spinach and mushrooms, repeating until you have three layers. After you get to the top layer of pasta, mix the excess cheese and sauce together in the cheese bowl, and spread across the top layer of pasta.
At this point you can either carry on, or let it cool, cover it with plastic wrap, and put it in the fridge for later. It'll keep just fine for 3 days.
OK - ready to serve it? Good. If you were doing this all in one fell swoop, you're oven's already pre-heated. If you're doing this later, be sure to pre-heat your oven to 375°.
Cover the lasagne with aluminum foil, and put it in the oven. After about a half hour remove foil, and continue to cook it for another 15 to 20 minutes, up to an hour. Remove from the oven, and let sit for about 5 to 10 minutes to let it set up.