Prepare the Eggplant: preheat the oven to 375 degrees. Line 2-3 baking pans with parchment paper or silicon baking mats. Layer each tray with the eggplant. Bake 20 minutes, then flip over and cook another 20 minutes.
Make the lentil filling: add diced onions in a large pot with a splash of water or veggie broth. Sauté over medium heat 3-4 minutes until translucent. Add carrots, crushed tomatoes and tomato paste to the pot, stirring well. Once everything is well incorporated, add the lentils and vegetable broth, basil and oregano.
Bring everything to a boil, then cover and reduce heat to simmer for 30 minutes. Stir frequently so as not to over cook.
Make the cashew ricotta cheese: take soaked cashews, and all ingredients and put in your food processor.
Make the "Meat": Using a food processor, pulse the garlic a few times, if using fresh. Then add the nuts (walnuts & sunflower seeds) and spices, and pulse again. Then add the mushrooms and tamari and pulse until there are no longer any big pieces of mushrooms left. Depending on your food processor, you may need to do this in 2 batches, as you don’t want the mixture to be too fine. However, don’t be too worried about it, because even if over mixed a bit, this mixture will still turn out well.
"Meat" continued: next, place the meat mixture onto a parchment lined baking sheet or use silicone sheets and bake for 15 to 20 minutes. Then remove from the oven and fold and turn the mixture over. Place back into the oven and bake for another 15 to 20 minutes or until cooked and dark brown in color.
After all the parts are prepared, Layer the Eggplant Lasagna: Spread 1/2 the Marinara sauce over the base of a large casserole dish. Then use some Marinara at each layer keeping 1/2 cup for the top.
Then cover with 1/3rd of the Eggplant, try to overlap as tight as possible.
Layer 1: spread 1/2 of the cooked Lentils OR Walnut Mushroom "Meat" across the Eggplant, followed by the Cashew (or Tofu) Ricotta.
Layer 2: repeat with Eggplant, remainder of Lentils or Walnut Mushroom "Meat" and another 1/3 of the Ricotta.
Top it off with the remainder of the Eggplant to the casserole, followed by the rest of the Ricotta.
Pour the remaining Marinara Sauce as the last layer, swirl with Ricotta.
Bake at 375 degrees for 35 minutes. It will bubble when it is done. Let sit for 10 minutes before you cut and serve.